We build a heat pump with our own hands. Homemade heat pumps for heating. How does a heat pump work
Heat pumps allow you to take scattered energy from the surrounding nature: air, water and earth, accumulate and direct it to heat the house. Energy is also used to heat water for washing or air conditioning in rooms. This makes it possible to save money by reducing the consumption of traditional heat sources: electricity, gas, firewood. In the article we will tell you how to make a heat pump with your own hands.
What is a geothermal pump
First you need to understand what a geothermal pump is, and on what principle it works, because it is he who is the heart of the entire device we are describing.
It's not a secret for anyone that above zero temperature is always maintained in the thickness of the earth. In the same state is the water under the ice. In this relatively warm environment, a closed pipeline with liquid is placed.
The scheme of operation of heat pumps is quite simple and is based on the inverse Carnot principle:
- The coolant, moving along the outer contour, is heated from the selected source and enters the evaporator.
- There he exchanges energy with the refrigerant (usually freon).
- Freon boils, passes into a gaseous state and is compressed by a compressor.
- Hot gas (it heats up in the range of 35–65 o C) enters another heat exchanger, in which it gives up its heat to the heating or hot water supply system of the house.
- The cooled refrigerant becomes liquid again and returns to a new circle.
Refrigerator pump
The main part of the system is the compressor. It is better to buy it ready-made in the store or use it from a refrigerator or air conditioner. All other components - evaporator, condenser, pipeline - can be assembled by yourself. Such an apparatus will consume energy only for compression and heat transfer, while generating 5 times more.
When using an old compressor, one must expect that its service life may be short and the system capacity will decrease. In addition, the power of a worn compressor may not be enough for the full operation of the system.
Some craftsmen went further and made a heat pump from a refrigerator, placing radiators inside it, heated by the heat of the earth. Positive temperature is constantly maintained inside, which makes the refrigerator work constantly, heating the radiator located behind it. Using a native radiator, they make a heat exchanger out of it (or make a home-made one), take away the heat generated by it.
The efficiency of such a heat pump is more suitable for demonstrating the operation of the device, since its efficiency is very low. In addition, the refrigerator is not designed for this mode of operation and can quickly fail.
Types of heat pumps
There are three types of pumps, depending on the heat source:
"soil-water"
"water-water"
"air-water"
Installation of the "soil-water" type uses the heat of the bowels. The temperature of the earth at horizons of more than 20 m always remains unchanged, therefore the pump can generate the necessary energy all year round. There are two mounting options:
- vertical shaft;
- horizontal manifold.
In the first case, a well is drilled with a depth of about 50–100 m and pipes with a circulating coolant, a special non-freezing liquid, are placed in it.
At a depth of 5 m, collectors are laid along which the coolant also moves. To heat a house with an area of 150 m 2, a plot of at least 250 m 2 is required, and it cannot be used for agricultural planting. Only decorative lawn and flower beds are allowed.
The water-to-water pump uses the energy of water from lakes, wells or wells. Some manage to extract heat even from drains. The main thing is that the filter does not clog and the metal does not collapse.
This type usually shows the highest efficiency, but it is not possible to install it in every suburban area, and permission must be obtained for the operation of groundwater. Such devices are more typical for industrial production.
The air-to-water design is less efficient than the first two, as output is greatly reduced in winter. On the other hand, during its installation it is not necessary to drill or dig anything. The unit is simply mounted on the roof of the house.
As already mentioned, it is preferable to buy a ready-made compressor. Any model used in air conditioners is suitable.
We assemble all other components ourselves:
- A stainless steel tank with a capacity of about 100 liters is taken as the condenser body. It is cut in half and inside a coil is mounted from a copper tube with a wall thickness of at least 1 mm. Threaded connections are soldered into the shell for connection to the circuit. After that, parts of the tank can be welded.
- For an evaporator, an 80 liter polyethylene bottle or a piece of pipe is perfect. A coil is also inserted into it and water inlets and outlets are supplied. The heat carriers are isolated from the external environment with a foam rubber “fur coat”.
- Now you need to put the entire system, solder the pipes and fill in the refrigerant. The amount of freon is very important for the correct operation of the pump, it is better to entrust this calculation to a heating engineer. He will be able to finally connect the installation and set up the compressor.
- It remains only to attach the outer contour. Its assembly will depend on the type of pump.
A vertical soil-water installation requires a well, a geothermal probe is lowered into it.
For a horizontal apparatus, a collector is assembled and buried in the ground at a depth that excludes freezing.
In the water-water system, the circuit consists of a network of plastic pipes through which the coolant will flow. Then all this must be fixed in the reservoir at the required depth.
The air-to-water pump manifold is also made and mounted on the roof of the house or nearby.
For stable operation and protection against breakdown, it is desirable to supplement the machine with the ability to manually start the compressor in case of a sudden power outage. The cost of such an installation is quite high. The factory pump is even more expensive. However, practice shows that the acquisition pays off in several years of operation.
Video
For the owners of private homes, the issue of heating the house is always acute. Central gas or water heating can be used, but other options can be explored. Such an alternative is a heat pump. You can save money with the help of an independent construction using old equipment.
Heat pumps are able to work from natural energy sources. The device generates heat without diesel or solid fuel.
When arranging the heating system, the main role is played by the heat pump. Its construction requires special attention.
The pump itself cannot generate heat, it simply transfers it into the house. This requires a small amount of electricity. It is enough to have a heat pump and an external energy source to heat the building. The pump works opposite to the refrigerator. The heat is taken from outside and sent to the room.
Heat pump diagram:
- The compressor is an intermediate element of the system;
- The evaporator is a low-potential energy transfer element;
- Throttle valve - freon moves through it to the evaporator;
- Condenser - in it the refrigerant is cooled and gives off its heat.
First, energy is released from natural sources and enters the evaporator. Further heat is transferred to freon. In the compressor, the refrigerant is pressurized and its temperature rises. Further, freon is sent to the condenser, where it is returned to the heating system. The refrigerant returns to the evaporator where the process is repeated.
Homemade heat pump from the refrigerator: stages of creation
A heat pump is quite an expensive device. But if you wish, you can build a device with your own hands from an old refrigerator or air conditioner. The refrigeration device has in its system two parts necessary for the pump - a condenser and a compressor.
Steps for assembling a heat pump from a refrigerator:
- First, the capacitor is assembled. It looks like a wavy element. In the refrigerator, it is located at the back.
- The condenser must be placed in a strong frame that retains heat well and tolerates high temperatures. In certain cases, it is necessary to cut the container in order to install the capacitor without problems. At the end of the installation, the container is welded.
- The next step is to install the compressor. The unit must be in good condition.
- The function of the evaporator is performed by an ordinary plastic barrel.
- When everything is prepared, you should fasten the elements together. The heat exchanger is attached to the heating system with PVC pipes.
So it turns out a homemade heat pump. Freon must be pumped by a professional, as the liquid is not easy to work with. In addition, for its injection, you must have special equipment.
Heat pumps made from old appliances are great for heating small commercial spaces.
The refrigerator can act as a radiator. You will need to make two air vents that will ensure its circulation. One branch receives cold air, the second - releases hot.
Types of heat pumps: the nuances of the freon-water heat exchanger
Heat pump controller and other elements of the water-water system
Pipes are placed in the nearest water in sufficient depth. It is important that the water does not freeze completely. The condenser is connected to the heating system of the house. The work itself has 4 stages.
Stages of operation of the water-to-water pump:
- The refrigerant receives heat from an external source, heats up and boils;
- Freon in the form of gas enters the compressor, where it is compressed under pressure;
- Heat transfer to the heating system, the refrigerant again assumes a liquid state;
- Freon returns to its original positions and is ready to receive heat.
The main thing in this system is the compressor. Freon will not be able to condense on its own if the temperature in the house is high. This will require increased pressure, which this element performs.
So the heat pump takes in external heat, adds its own, and also heats up in the compressor. The water source is cooled and the house is heated. The controller guarantees automatic operation. All data are marked on the pressure and temperature sensors.
How to make a heat pump with your own hands from an old refrigerator (video)
The heat pump has a simple principle of operation. Alteration of an existing split system requires special knowledge, but you can draw energy from natural sources. They can serve as a well, soil, reservoir, air.
If it is impossible or too expensive to heat a private house with gas, and it is not convenient to use solid fuel, why not extract energy directly from the environment? One of the most efficient options to get the required joules is a water to water heat pump. In the West, the industrial production of such units has long been established and is in high demand. However, their cost is quite high. Therefore, the question of creating a heat pump with your own hands remains very relevant.
How does a heat pump work and how does it work?
Roughly speaking, a heat pump works like a refrigerator, but in reverse. The refrigerator removes some of the heat to the outside to lower the temperature inside the chamber. Therefore, the back wall of the refrigerator noticeably heats up. The heat pump “cools” the environment by heating the coolant that circulates in the home heating system.
Typically, water-to-water heat pumps consist of the following set of devices:
- outer contour;
- inner contour;
- evaporator;
- condenser;
- compressor.
The outer circuit is a pipe through which groundwater circulates. It enters the system from a well, passes through the outer loop, giving off low-potential thermal energy to the system, and then is discharged into another well. Sometimes inside the outer circuit, immersed in water, there is a special liquid called "brine". This is also a very effective way to collect heat from the environment.
Note! If there is an open reservoir near the house, it can also be used as a heat source. At the same time, there is no need to drill wells for the intake and discharge of groundwater.
Ground water heat enters the evaporator. The refrigerant under pressure enters here through the capillary opening. The decrease in pressure causes the evaporation process and the heat from the inner walls of the evaporator is transferred to the refrigerant. The gaseous refrigerant enters the compressor, where it is compressed, after which it is sent to the condenser.
Here, the refrigerant again passes into a liquid state, and the resulting energy is used to heat the coolant that circulates in the pipes of the heating system of the house. Thus, the low-potential thermal energy of water is converted into energy with a high potential and allows you to heat the house quite efficiently even in severe frosts. This process is visualized in the water-to-water heat pump diagram.
The water-to-water heat pump diagram shows the process of obtaining low-potential thermal energy from the environment into high-potential energy for heating a house and heating water
The performance of a heat pump largely depends on fluctuations in water temperature. The more stable the temperature, the better the heating. In the well, the water temperature throughout the year fluctuates between 7-12 degrees, which makes it possible to use the equipment very efficiently. To automate the operation of the device, a thermostat is used, which turns the compressor on and off, maintaining the temperature in the rooms at a certain level.
How to make such a device yourself?
A homemade water-to-water heat pump is a set of ready-made units that must be connected in the correct sequence. It looks simple, but in practice the whole thing can be spoiled due to the lack of competent calculations. They are necessary to find out the optimal compressor power, the diameter of the heat exchanger pipe, as well as other system parameters. Non-specialists have several options for solving this problem:
- use special software (for example, CoolPack 1.46 and Copeland programs);
- use online calculators that are offered on the websites of manufacturers of such equipment;
- invite a specialist who will help you calculate everything for a fee or out of the kindness of your heart.
So, now about each detail in more detail.
Item #1 - Compressor
The easiest way to get a suitable compressor is to remove it from the air conditioner, for example, from an LG brand split system. The 7-watt compressor has a capacity of 9.7kW in heat production and 7.5kW in cooling. An additional advantage of such compressors is the low noise level during operation.
The compressor for a water-to-water heat pump can be removed from an old air conditioner. It is preferable to choose a model that is suitable for power and operates silently.
Many compressors use R22 freon, the boiling point of which is -10, condensing - +55. In 2030, this refrigerant will be banned from use. A worthy alternative can be a more "young" freon R422. However, you can change the refrigerant not only when creating a heat pump, but also at any suitable time.
Item #2 - Capacitor
For the manufacture of the condenser, a stainless steel tank of approximately 120 liters can be used. It is cut in half, a copper coil is mounted inside, connections with a two-inch thread are welded, then the halves of the tank are connected by welding. The area of the coil through which the refrigerant will circulate is calculated by the formula:
PZ \u003d MT / 0.8RT, where:
- ПЗ - coil area;
- МТ - Power of heat produced by the system, kW;
- 0.8 - coefficient of thermal conductivity in the interaction of water and copper;
- RT - the difference in water temperature at the inlet to the system and at the outlet of it, degrees Celsius.
For the manufacture of the coil, a half-inch copper pipe, a special refrigeration or clean plumbing is suitable. The recommended pipe wall thickness is 1-1.2 mm. To turn a pipe section of the required length into a coil, it is enough to wind it around any suitable cylinder, for example, a gas cylinder. The ends of the coil are brought out using plumbing adapters. To ensure the tightness of the connection, use flax and a clamping nut.
To make a coil for the condenser of a water-to-water heat pump, you need to carefully wind the copper pipe around the cylinder. A metal rail will help fix the pitch of the turns
Please note that the freon inlet must be located at the top of the condenser to prevent the formation of bubbles.
Item #3 - Evaporator
A plastic barrel with a volume of 127 liters is suitable for the role of the evaporator. It is more convenient if it has a wide neck. The evaporator is calculated in the same way as the condenser. Copper pipe can be twisted with copper wire, without any insulation.
A homemade evaporator for a water-to-water heat pump can be made from a plastic barrel with a wide mouth. The coil can be placed in a smaller container, but it is more convenient to work with a barrel with a volume of more than 120 liters
Experts recommend using flooded-type evaporators for home-made heat pumps, in which the liquefied refrigerant enters the water from below and evaporates at the top. Adapters can be made from the necks of ordinary plastic bottles, which are fixed with flax and sealant. Standard sewer pipes are suitable for supplying and discharging water. When installing a thermostatic valve, before starting to solder the equalization line pipe, wrap it with a damp cloth, since this element cannot be heated to more than 100 degrees.
Assembly and filling with freon
To assemble the prepared devices into a single system, you will need a welding machine. At the entrance to the compressor, it is recommended to make a filling valve, which will come in handy in the future. Then, using a special vacuum pump, the system should be checked for vacuum.
To fill the system with freon, you will need a cylinder containing at least 2 kg of refrigerant. After refueling, it is recommended to wait a few days, checking the pressure in the system. If it remains constant, then there are no leaks. If the pressure drops, you can determine the leaks in the simplest way: using soap suds. Inexperienced craftsmen are better off contacting a master who will fill the equipment professionally and reliably.
For automatic control of the system operation, it is recommended to use a 40A single-phase starting relay, a 16A fuse, an electrical panel and a DIN rail. You will need two capillary temperature sensors: at the outlet of the system (recommended maximum temperature is 40 degrees) and at the outlet of the evaporator (shutdown temperature is 0 degrees to prevent freezing of the system). If a controller is used to take into account the readings of both temperature sensors, it should be remembered that its settings may be lost during a power outage.
This is what one of the options for a home-made water-to-water heat pump looks like. On top of the device is closed with a metal case, on which the control panel is mounted.
After the system is ready, and its elements are placed in convenient places, two separate wells should be built for the intake and discharge of groundwater and the external circuit should be connected to the system. In areas where drilling of wells is associated with certain problems, this issue should be dealt with in the first place. If wells cannot be drilled, it may be necessary to choose another heat pump option, such as ground-to-water.
The following video demonstrates the operation of a homemade heat pump pump:
Before proceeding with the manufacture of a heat pump, it is necessary to assess the level of thermal insulation of the building and increase it to the maximum level. Otherwise, the efficiency of this system will tend to zero.
It is best to use a heat pump complete with low-temperature heating systems. Most often, the unit is connected to the "" system. Successful experience can be with systems of warm walls, large radiators, etc. The efficiency of the system will be the higher, the smaller the temperature difference between the outer and inner circuits.
To reduce the cost of building a heat pump, it is recommended to use an additional heat source: gas, electric or solid fuel boiler. The required power and construction costs of a heat pump will be lower, and the cost of heating a home will be reduced.
DIY heat pump
From the beginning, there was only a house under construction on 2.5 floors. Square:
1st floor 64 m2,
2nd floor 94 m2,
2.5 floor 55 m2,
garage 30 m2.
Bought secondhand from the start. gas generating boiler on firewood with a capacity of 40 kW But as the time for the installation approached, I completely ceased to please the prospect of harvesting firewood, the eternal struggle with garbage, and by nature I am more of a dervish, I can easily not appear at home for a couple of days.
(Homemade heat pump, gas generating boiler, Evaporator, compressor, Condenser, homemade heat pump, heat pump, DIY heat pump, alternative energy)
And then I leaned towards liquefied gas. I note that a low-pressure natural gas pipe runs 1.5 km from the house. But our population density is low, and pulling a pipe for me alone + project + installation just plunges me into horror.
I also can’t put a barrel on several cubes on the site. I don't want to ruin the look. I decided to install a couple of cabinets with a battery of 80-liter propane tanks of 6 pieces each.
The gas operator assured that they themselves come, change themselves, you just call us. The inconvenience included only a headache once every three weeks, as well as the possibility of an unauthorized entry of a gas car into my future cobblestone-passenger parking lot, rolling and dragging cylinders along it. In general, the human factor. But the case solved the problem:
idea to build DIY heat pump
idea construction heat pump hatched for a long time. But the stumbling block was single-phase electricity and an antediluvian meter for 20 amperes of maximum load. It is not yet possible to change the eclectic power supply to a three-phase one or add power in our area. But unexpectedly, they planned to change the meter to a new one, 40 amperes.
Having estimated, I decided that this would be enough for partial heating (I did not plan to use the 2.5th floor in winter), I undertook to probe the heat pump market. The prices requested in one company (single-phase HP for 12 kilowatts) made us think:
Thermia Diplomat TWS 12 kWh 6797 euros
Thermia Duo 12 kWh 5974 euros
It required at least 45 amps for starting current.
In addition, since it was planned to take heat removal from well water, there was no confidence in the debit of my well. In order not to risk such an amount, I decided to assemble the TN myself, since some skills were from life. He worked when he was a manager for the distribution of ventilation and air conditioning equipment.
Homemade heat pump concept:
I decided to make a HP from two single-phase compressors of 24,000 BTU each (7 kWh in cold). Thus, a cascade with a total thermal power of 16-18 kilowatts was obtained with electricity consumption at COP3 of about 4-4.5 kilowatts / hour. The choice of two compressors was due to lower starting currents, since it was thought not to synchronize their starts. As well as the phased commissioning. So far, only the second floor has been inhabited and one compressor will suffice. Yes, and having experimented on one, then it will be bolder to complete the second section.
Refused to use plate heat exchangers. Firstly, for reasons of economy, I did not want to pay 389 euros apiece for Danfos. And secondly, to combine the heat exchanger with the capacity of the heat accumulator, that is, by increasing the inertia of the system, thereby killing two birds with one stone. And I didn’t want to do water treatment for delicate plate heat exchangers, thereby reducing efficiency. And my water is bad, with iron.
The first floor is already equipped with a heated floor piping with an approximate step of 15 cm.
The second floor has radiators (thank God, it was enough stinginess to put them with 1.5 thermal reserves earlier). Coolant intake from the well (12.5 m. Installed on the first layer of dolomite. +5.9 measured on 03.2008). Disposal of waste water into the general sewerage system (two-chamber sump + infiltration soil absorber). Forced circulation in heat removal circuits.
Here is the schematic:
1. Compressor (so far one).
2. Capacitor.
3. Evaporator.
4. Thermal expansion valve (TRV)
It was decided to abandon other safety devices (filter-drier, viewing window, pressure switch, receiver). But if anyone sees the point of using them, I will be glad to hear advice!
To calculate the system, I downloaded the CoolPack 1.46 calculation program from the Internet.
And a good program for the selection of Copeland compressors.
Compressor:
I managed to buy from an old friend of the refrigeration, a little used compressor from a 7 kilowatt split system of some kind of Korean air conditioner. I got it almost for nothing, and I didn’t lie, the oil turned out to be completely transparent inside, it worked for only a season and was dismantled due to a change in the concept of the premises by the customer.
The compressor turned out to have a capacity of 25,500 Btu, which is about 7.5 kW. in cold and about 9-9.5 in heat. What made me happy, in the Korean split there was a solid compressor of the American company Tecumset. Here is his data:
The compressor is on R22 freon, which means a slightly higher efficiency. Boiling point -10c, condensation +55c.
Lapsus number 1: From old memory, I thought that only scroll type compressors (scroll) are installed on household split systems. Mine turned out to be piston ... (It looks a little oval and the engine winding is hanging inside). Bad, but not fatal. To its minuses, a quarter less resource, a quarter lower efficiency, a quarter more noisy. But nothing, experience is the son of difficult mistakes.
Important: Freon R22 under the Montreal Protocol will be fully decommissioned by 2030. Since 2001, the commissioning of new installations has been prohibited (but I am not introducing a new one, but have modernized the old one). Since 2010, the use of R22 freon is only used. BUT at any time you can transfer the system from R22 to its replacement R422. And no more trouble.
I fixed the compressor on the wall with L-300mm brackets. If I later mount the second one, I lengthen the existing ones using the U-profile.
2. Capacitor:
I successfully purchased a stainless steel tank of about 120 liters from a welder friend.
(By the way, all welded manipulations with the tank were performed free of charge by a respected welder. But he asked to mention his modest role for history!)
It was decided to cut it into two parts, insert a coil from a copper pipe of a freon guide, and weld it back. At the same time, weld in several technical inch-threaded connections.
The formula for calculating the surface area of a copper coil pipe:
M2 = kW/0.8x?t
M2 is the area of the coil pipe in square meters.
kW - Heat dissipation power of the system (with compressor) in kilowatts.
0.8 - coefficient of thermal conductivity of copper / water under the condition of counterflow of media.
T is the difference between the water temperature at the inlet and outlet of the system (see diagram). For me it is 35s-30s = +5 degrees Celsius.
So it turns out about 2 square meters of the heat exchange area of the coil. I slightly reduced it, since the temperature at the freon inlet is about + 82 ° C, this can save a little. But as I wrote earlier Santa Claus, not more than 25% of the size of the evaporator!!!
The simulated system in CoolPack showed a Cop of 2.44 on stock heat exchanger tube diameters. And Cop 2.99 with a diameter one step higher. And this is to my advantage, since in the future I expect to attach a second compressor to this branch. I decided to use a ½ inch (or 12.7 mm outer diameter) copper pipe, refrigeration. But, I think, you can use the usual plumbing, it’s not like that there and there will be a lot of dirt inside.
Lapsus number 2: I used a pipe with a wall of 0.8 mm. In fact, she turned out to be very gentle, a little crushed and she already hesitates. It is difficult to work, especially without special skills. Therefore, I recommend taking a 1mm or 1.2mm wall pipe. So the durability will be longer.
Important: The freon conductor of the coil enters the condenser from above, exits from below. So condensing liquid freon will accumulate at the bottom and leave without bubbles.
Thus, having taken 35 meters of the pipe, he turned it into a coil, winding it around a convenient cylindrical object (cylinder).
At the edges, I fixed the turns with two aluminum slats for strength and equal spacing of the loops.
The ends were brought out with the help of plumbing transitions to a copper tube for twisting. He slightly drills them from a diameter of 12 to 12.7 mm, and instead of a compression ring, after assembly, he wound flax on a sealant and clamped it with a lock nut.
3. Evaporator:
The evaporator did not require high temperature, and I opted for a 127 liter wide-mouthed plastic container.
Important: A 65 liter barrel would be ideal. But I was afraid, the ¾ pipe bends very badly, so I took a larger size. If anyone has other sizes or has a good pipe bender and work skills, then you can take a chance on this size. With a 127 liter drum, my HP increased the expected dimensions by 15 cm up, 5 cm deep and 10 cm wide.
I calculated and manufactured the evaporator according to the same principle as that of the condenser. It took 25 meters of pipe ¾ 'inch (19.2mm outer) with a wall of 1.2mm. As stiffening ribs, I used segments of the UD profile for the installation of gypsum plaster. Twisted with ordinary copper electrical wire without insulation.
Important: Flooded type evaporator. That is, the liquid phase of freon enters the cooled water from below, evaporates and in the gaseous state rises up to the compressor. This is better for heat transfer.
Transitions can be taken from plastic drinking pipes PE 20 * 3/4 'with an external thread, unscrewed from the barrel with lock nuts and a seal made of flax and sealant. The supply and drainage of water was made from ordinary sewer pipes and rubber sealing cuffs inserted by surprise.
The evaporator was also mounted on L-400mm brackets.
4. TRV:
Acquired TRV from Honeywell (former FLICA). For my power, it took a 3mm nozzle to it. And a pressure equalizer.
Important: TRV during soldering cannot be overheated above +100c! Therefore, I wrapped it with a cloth soaked in water to cool it. Please do not be horrified, after the raid I cleaned it with fine sandpaper.
I soldered the equalization line tube as it should be in the installation instructions for the expansion valve.
Assembly:
Bought a kit for hard soldering Rotenberg. And electrodes 3 pieces with 0% silver content and 1 piece with 40% silver content for soldering in the compressor side (vibration resistant). With their help, I assembled the entire system.
Important: Take the Maxigaz 400 bottle (yellow bottle) right away! It is not much more expensive than Multigas 300 (red), but the manufacturer promises up to +2200c flame. But this is not enough for ¾ 'pipe. Soldered badly. I had to contrive, use a heat shield, etc. Ideally, of course, have an oxygen burner.
Yes, and you need to solder a filling pipe with a nipple to connect the hose to the system. I don't remember its exact name off the top of my head.
It was soldered at the compressor inlet. Nearby, the inlet pipe of the equalizer of the expansion valve is also visible. It is soldered after the evaporator, thermostatic expansion valve, but before the compressor.
Important: We solder the filling pipsik by first unscrewing the nipple from it. Neither from the heat, the nipple seal will definitely fail.
I did not use reducing tees, as I was afraid of a decrease in reliability from additional solder joints near the compressor. Yes, and the pressure in this place is not great.
Freon charging:
collected, but not filled The system must be evacuated with water. It is better to use a vacuum pump, if not, then the craftsmen adapt a conventional compressor from an old refrigerator. You can simply blow through the system with freon by squeezing out the air, but I didn’t tell you this, because you can’t do that!
Freon cylinder of the smallest capacity. The system will not need more than 2 kg at all. freon. But how rich.
I also bought a pressure gauge. But not a special freon one for 10 USD, but an ordinary one for a pumping station for 3.5 USD. On it and guided when filling.
I filled the system as much as possible with the help of the internal pressure of freon in the cylinder. I let it stand for a couple of days, the pressure did not drop. So there is no leak. Additionally, I missed all the connections with soapy foam, it did not bubble.
Important: Since in my case the filling nipple is soldered immediately in front of the compressor (in the future, the pressure in this place will be measured when setting up), in no case should the system be filled with liquid freon with the compressor running. The compressor will probably fail. Only in the gaseous phase - balloon up!
Automation:
You need a single-phase starting relay, and at the same time, for a very decent starting current of about 40 A! Automatic fuse From the group to 16A. Electrical panel with DIN rail.
I also installed two temperature switches with copelar thermal sensors. One put on the water at the outlet of the condenser. I set it to about 40 degrees to turn off the system when the water reaches this temperature. And to the outlet of water from the evaporator to 0 degrees, so that it emergency shuts down the system and does not unfreeze it by chance.
In the future, I'm thinking of purchasing a simple controller that takes these two temperatures into account. But besides the appearance and visibility of use, it also has a drawback - the programmed values are lost even with a short power outage. While thinking.
Run (trial):
Before starting, I pumped about 6 bar of pressure from the cylinder into the system. More did not work, and there is no need. I threw a temporary wire, connected the starting capacitor. I filled the containers with water first. They stood for a day, filled, and therefore, at the time of launch, they had a room temperature of about + 15C.
Solemnly turned on the machine. He was knocked out immediately. Still, the same. During this short interval, you can hear the engine buzzing, but not starting. I moved the terminals on the capacitor (for some reason there are three of them). Turned the machine back on. The pleasant rumble of a running compressor caressed my ears!!!
The suction pressure immediately dropped to 2 bar. Opened the freon bottle to fill the system. According to the plate, I calculated the required boiling pressure of freon.
For my required +6 inlet and +1 outlet water, a boiling point of -4c is required. Freon boils at this temperature at a pressure of 4.3 kg.cm. (bar) (atmospheres). The table can also be found online.
No matter how I tried to set the exact pressure, nothing worked. The system has not yet been brought to operating temperature. Therefore, premature adjustments are only approximate.
Five minutes later, the feed reached about +80 degrees. While the uninsulated evaporation pipe was covered with light frost. The water in the condenser after ten minutes to the touch has already warmed up to +30 - +35. The water in the evaporator is close to 0c. In order not to unfreeze something, I turned off the system.
Summary: Trial run showed full working capacity systems. Anomalies were not observed. Further adjustments of the expansion valve and freon pressure will be required after connecting the heating circuit and cooling with well water. That's why continuation of the photo essay and report in about two to three weeks when I figure out this part of the work.
By that time, I think:
1. Connect the space heating circuit and the well water heat exchange circuit.
2. Carry out a full cycle of commissioning.
3. Make some kind of case.
4. Draw conclusions and give a short summary.
Important: TN turned out not so small in size. By using plate heat exchangers instead of capacitive heat exchangers, you can save a lot of space.
The cost of manufacturing a heat pump with an approximate capacity of 9 kilowatt hours in terms of heat:
Capacitor:
Stainless steel tank 100 liters - 25 c.u.
Stainless steel electrodes - 6 c.u.
Couplings stainless steel - 5 c.u.
Services of a welder (lunch) - 5 c.u.
Copper pipe 12.7 (1/2”)*0.8mm. 35 meters - 105 USD
Copper pipe 10*1 mm. 1 meter - 3 c.u.
Air blower Du 15 - 5 c.u.
Safety valve 2.5 bar - 4 c.u.
Drain valve Du 15 - 2 c.u.
Total: $163 (in comparison, plate heat exchanger Danfos 389 c.u.)
Evaporator:
Plasma barrel. 120 liters - 12 c.u.
Copper pipe 19.2 (3/4”)*1.2mm. 25 meters - 130 USD
Copper pipe 6*1mm. 1 meter - 2 c.u.
Honeywell thermostatic valve (nozzle 3mm) - 42 USD
Brackets L-400 2 pieces - 9 c.u.
Drain valve Du 15 - 2 c.u.
Transitions to copper (set) - 3 c.u.
RVS pipe 50-1m. 2 pieces - 4 c.u.
Rubber transitions 75*50 2 pieces - 2 c.u.
Total: $206 (in comparison, plate heat exchanger Danfos 389 c.u.)
Compressor:
Compressor little used 7.2 kW (25500 btu) - 30 c.u.
Brackets L-300 2 pieces - 8 c.u.
Freon R22 2 kg. - 8 c.u.
Mounting kit - 4 c.u.
Total: $50
Mounting kit:
Blowtorch ROTENBERG (set) - 20 USD
Hard soldering electrodes (40% silver) 3 pieces - 3.5 c.u.
Hard soldering electrodes (0% silver) 3 pieces - 0.5 c.u.
Manometer for freon 7 bar - 4 c.u.
Filling hose - 7 c.u.
Total: $35
Automation:
Starter relay single-phase 20 A - 10 c.u.
Built-in electric shield - 8 c.u.
Single-phase fuse C16 A - 4 c.u.
Total: $22
Total in general 476 c.u.
Important: At the next stage, more circulation pumps Calpada 25 / 60-180 60 c.u. will be required. and Calpeda 32/60-180 78 c.u. Although they will be taken out of the chapels of my boiler, they usually refer to the boiler itself.
Heat pump, alternative energy, heating, energy saving, do-it-yourself heat pump, homemade heat pump
Since ancient times, mankind has been "accustomed" to using available natural resources. energy carriers, which are simply burned to produce heat or to be converted into other forms of energy. People also learned to use the hidden potential of water flows - they started from water mills and reached powerful hydroelectric power plants. However, what seemed quite sufficient a hundred years ago, today can no longer satisfy the needs of the growing population of the Earth.
Firstly, natural "pantries" are still not bottomless, and energy production is becoming more and more difficult every year, moving to hard-to-reach regions or even to sea shelves. Secondly, the combustion of natural raw materials is always associated with emissions of combustion products into the atmosphere, which, with the current huge volumes of such emissions, has already put the planet on the brink of an ecological disaster. The energy of hydroelectric power plants is not enough, and the violation of the hydrological balance of rivers also entails a lot of negative consequences. Nuclear power, which was once viewed as a "panacea", after a number of high-profile man-made disasters raises a lot of questions, and in many regions of the planet, the construction of nuclear power plants is simply prohibited by law.
However, there are other, almost inexhaustible sources of energy that have become widely used relatively recently. Modern technologies have made it possible to very effectively use the energy of wind, sunlight, ocean tides, etc. to produce electricity or heat. One of the alternative sources is the thermal energy of the earth's interior, water bodies, and the atmosphere. It is on the use of such sources that the operation of heat pumps is based. For us, such equipment is still included in the category of “exotic novelties”, and at the same time, many Europeans heat their homes in this way - for example, in Switzerland or Scandinavian countries, the number of houses with such systems has exceeded 50%. Gradually, this type of heat generation is beginning to be practiced in Russian open spaces, although the prices for acquiring a high-tech set of equipment still look very frightening. But, as always, there are master enthusiasts who show their creativity and assemble heat pumps with their own hands.
The publication is aimed at ensuring that the reader can take a closer look at the principle of operation and the basic device of heat pumps, learn about their advantages and disadvantages. In addition, we will talk about successful experiences in creating existing installations on our own.
How a heat pump works
Not everyone thought about it, but around us there are many heat sources that “work” all year round and around the clock. For example, even in the most severe cold, the temperature under the ice of a frozen reservoir still remains positive. The same picture and when deepening into the thickness of the soil - below the border of its freezing, the temperature is almost always stable and approximately equal to the average annual characteristic for this region. The air also carries a considerable thermal potential.
Perhaps someone will be confused by the seemingly low temperatures of water, soil or air. Yes, they belong to low-potential energy sources, but their main “trump card” is stability, and modern technologies based on the laws of thermal physics allow even a slight difference to be converted into the necessary heating. Yes, and, you see, when the frost is 20 degrees outside in winter, and the soil has 5 ÷ 7 degrees below the freezing level, then such an amplitude difference is already quite decent.
It is this property of the continuity of the supply of low-potential energy that is embedded in the heat pump circuit. In fact, this unit is a device that "pumps" and "concerts" the heat taken from an inexhaustible source.
You can draw some analogy with the familiar refrigerator. The products that are placed in it for cooling and storage and the air entering the chamber when the door is opened are also not too hot. But if you touch the condenser heat exchange grate on the back wall of the refrigerator, then it is either very warm or even hot.
So why not use this principle to heat the coolant? Of course, the analogy with the refrigerator is not direct - there is no stable external heat source, and electricity is mostly wasted. But in the case of a heat pump, such a source can be found (arranged), and then it will turn out to be a "reverse refrigerator" - the main focus of the unit will be precisely on obtaining heat.
On what principle does it work?
It is a system of three circuits with coolants circulating through them.
- In the heat pump housing itself (pos. 1) there are two heat exchangers (pos. 4 and 8), a compressor (pos. 7), a refrigerant circuit (pos. 5), adjustment and control devices.
- The first circuit (pos. 1) with its own circulation pump (pos. 2) is placed ( immersed) in a source of low-grade heat (their device will be discussed below). Receiving thermal energy from an external uninterruptible source (shown by a wide pink arrow), heated by only a few degrees (usually, when using probes or collectors in the ground or in water - up to 4 ÷ 6 ° FROM), the circulating coolant enters evaporator heat exchanger(pos. 4). Here, the primary transfer of heat received from the outside takes place.
- The refrigerant used in the internal pump circuit (pos. 5) has an extremely low boiling point. Usually one of the modern, environmentally friendly freons, or carbon dioxide (essentially liquefied carbon dioxide) is used here. It enters the evaporator inlet (pos. 6) in a liquid state, at reduced pressure - this provides an adjustable throttle (pos. 10). The special shape of the capillary inlet and the shape of the evaporator contribute to the almost instantaneous transition of the refrigerant to a gaseous state. According to the laws of physics, evaporation is always accompanied by a sharp cooling and absorption of ambient heat. Since this section of the internal circuit is located in the same heat exchanger with the primary circuit, freon takes thermal energy from the coolant, while cooling it (wide orange arrow). The cooled coolant continues to circulate and again gains thermal energy from an external source.
- The refrigerant, already in a gaseous state, transferring the heat transferred to it, enters the compressor (pos. 7), where, under the influence of compression, its temperature rises sharply. Further, it enters the next heat exchanger (pos. 8), in which the condenser and pipes of the third circuit of the heat pump are located. (pos. 11).
- Here, a completely opposite process occurs - the refrigerant condenses, turning into a liquid state, while giving up its heat to the third circuit coolant. Further, in a liquid state at high pressure, it passes through a throttle, where the pressure decreases, and the cycle of physical transformations of the aggregate state of the refrigerant is repeated again and again.
- Now goes to the third circuit (pos. 11) of the heat pump. Through the heat exchanger (pos. 8), thermal energy is transferred to it from the refrigerant heated by compression (wide red arrow). This circuit has its own circulation pump (pos. 12), which ensures the movement of the coolant through the heating pipes. However, it is much more reasonable to use an accumulating, carefully insulated buffer tank (pos. 13), in which the transferred heat will accumulate. The accumulated supply of thermal energy is already spent for the needs of heating and hot water supply, being spent gradually, as needed. Such a measure allows you to insure against power outages or use a cheaper nightly tariff for the electricity needed to operate the heat pump.
If a buffer storage tank is installed, then a heating circuit (pos. 14) with its own circulation pump (pos. 15) is already connected to it, ensuring the movement of the coolant through the system pipes (pos. 16). As already mentioned, there may be a second circuit, which provides hot water for domestic needs.
The heat pump cannot work without electricity - it is required for the operation of the compressor (wide green arrow), and the circulation pumps in the external circuits also consume electricity. However, as the developers and manufacturers of heat pumps assure, the consumption of electricity is incomparable with the received “volume” of thermal energy. So, with proper assembly and optimal operating conditions, there is often talk of 300 percent or more efficiency, that is, with one kilowatt of electricity spent, a heat pump can produce 4 kilowatts of thermal energy.
In fact, such a statement about efficiency is somewhat incorrect. Nobody canceled the laws of physics, and efficiency above 100% is the same utopia as " perpetummobile"- perpetual motion machine. In this case, we are talking about the rational use of electricity for the purpose of "pumping" and converting energy coming from an inexhaustible external source. Here it is more appropriate to use the concept of COP (from the English "coefficient of performance") which in Russian is often called the “heat conversion coefficient”. In this case, indeed, values \u200b\u200bthat exceed one can turn out:
CO R = Qn / a, where:
CO R is the coefficient of heat conversion;
QP- the amount of thermal energy received by the consumer;
BUT- the work performed by the compressor unit.
There is one more nuance that is often simply forgotten - not only the compressor, but also circulation pumps in external circuits require a certain amount of energy for the normal functioning of the pump. Their power consumption, of course, is much less, but, nevertheless, it can also be taken into account, and this is often simply not done for marketing purposes.
The total amount of thermal energy received can be spent:
1 - the optimal solution is a system of warm water floors. As a rule, heat pumps give a "rise" in temperature to a level of about 50 ÷ 60 ° FROM- this is enough for underfloor heating.
2 - domestic hot water supply. Usually in DHW systems, the temperature is maintained at this level - about 45 ÷ 55 ° С.
3 - but for conventional radiators, such heating will be clearly not enough. The way out is to increase the number of sections or use special low-temperature radiators. Convection type heaters will also help to solve the issue.
4 - one of the most important advantages of heat pumps is the ability to switch them to the "opposite" mode of operation. In the summer, such a unit can perform the function of air conditioning - taking heat from the premises and transferring it to the ground or a reservoir.
Sources of low-potential energy
What sources of low-potential energy are capable of using heat pumps? This role can be played by rocks, soil at different depths, water from natural reservoirs, or underground aquifers, atmospheric air or warm air streams vented from buildings or industrial process units.
A. Use of thermal energy soils
As already mentioned, below the level of soil freezing characteristic of this region, the soil temperature is stable throughout the year. This is what is used for the operation of heat pumps according to the "soil - water" scheme.
Schematic diagram of the extraction of energy "soil - water" To create such a system, special surface thermal fields are being prepared, on which the upper layers of soil are removed to a depth of about 1.2 ÷ 1, 5 meters. They contain contours made of plastic or metal-plastic pipes with a diameter, as a rule, of 40 mm. The efficiency of heat energy removal depends on local climatic conditions and on the total length of the circuit being created.
Tentatively, for central Russia, you can operate with the following ratios:
- Dry sandy soils - 10 W of energy per linear meter of pipe.
- Dry clay soils - 20 W / m.
- Wet clay soils - 25 W / m.
- Clay rock with a high location of groundwater - 35 W / m.
Despite the apparent simplicity of such heat transfer, the method is by no means always the optimal solution. The fact is that it involves a very significant amount of earthwork. What looks simple in a diagram is much more difficult in practice. Judge for yourself - in order to "remove" even only 10 kWt of thermal energy from the underground circuit on clay soil, about 400 meters of pipe will be required. If we also take into account the mandatory rule that between the turns of the circuit there must be an interval of at least 1, 2 meters, then for laying a plot of 4 acres (20 × 20 meters) will be required.
Establishing a field for extracting heat from the ground is an extremely large-scale and time-consuming task. First, not everyone has the opportunity to allocate such a territory. Secondly, any buildings are completely excluded in this area, since there is a high probability of damage to the circuit. And thirdly, the extraction of heat from the soil, especially with poor-quality calculations, may not pass without a trace. The effect of overcooling of the site is not excluded, when summer heat cannot fully restore the temperature balance at the depth of the contour. This can negatively affect the biological balance in the surface layers of the soil, and as a result, some plants simply will not grow in a supercooled area - such a kind of local effect of the "ice age".
B. Thermal energy from wells
Even the small size of the site will not be an obstacle to organizing the care of thermal energy from a drilled well.
As a source of low-grade heat - a deep well The temperature of the soil with increasing depth only becomes more stable, and at depths of more than 15 — 20 meters is firmly on the 10-degree mark, increasing by two ÷ three degrees for every 100 m of diving. Moreover, this value is absolutely independent of the time of year or the vagaries of the weather, which makes the well the most stable and predictable source of heat.
A probe is lowered into the wells, which is a U-shaped loop of plastic (metal-plastic) pipes with a coolant circulating through them. Most often, several wells are made with a depth of 40 ÷ 50 and up to 150 meters, no closer than 6 m from one another, which are connected either in series or with a connection to a common collector. The heat transfer of the soil with this arrangement of pipes is much higher:
- With dry sedimentary rocks - 20 W / m.
- Rocky soil layers or water-saturated sedimentary rocks - 50 W / m.
- Solid rocks with high thermal conductivity - 70 W / m.
- If you are lucky, and you get an underground aquifer - about 80 W / m.
In case of insufficient space or difficulties in deep drilling due to the characteristics of the soil, several inclined wells can be performed with beams from one point.
By the way, in the event that the well falls on an aquifer with a stable debit, then an open primary heat exchange circuit is sometimes used. In this case, water is pumped from a depth by a pump, participates in heat exchange, and then, cooled, is discharged into a second well of the same horizon, to located oncertain distance from the first (this is calculated when designing the system). At the same time, water intake for domestic needs can be organized.
The main disadvantage of the downhole method of heat extraction is the high cost of drilling, which is very difficult or simply impossible to carry out on our own without the appropriate equipment. In addition, well drilling often requires permits from environmental authorities. By the way, the use of direct heat exchange with reverse water discharge into the well may also be prohibited.
Can you drill a well yourself?
Of course, this is an extremely difficult task, but there are technologies that allow, under certain conditions, to perform it independently.
About how you can - in a special publication of our portal.
B. Use of water bodies as heat sources
A reservoir of sufficient depth located near the house may well become a good source of thermal energy. Water, even in winter, under the upper crust of ice remains in a liquid state, and its temperature is above zero - this is what the heat pump needs.
Approximate heat transfer from a circuit immersed in water is 30 kW / m. This means that in order to get a return of 10 kW, a circuit of the order of 350 m is required.
Such collector circuits are mounted on land from plastic pipes. Then they move into the pond and dive to the bottom, to the depths not less than 2 meters, for which loads are attached at the rate of 5 kg per 1 linear meter of pipe.
Then it executes thermally insulated laying pipes to the house and connecting them to thermal heat exchanger pump.
However, one should not think that any body of water is fully suitable for such purposes - again, very complex heat engineering calculations will be needed. For example, a small and not deep enough pond or a small, quiet stream, not only can they not cope with the task of uninterrupted supply of low-potential energy - they can simply be completely frozen to the bottom, thereby killing all the inhabitants of the reservoir.
Advantages of water heat sources - there is no need for drilling, earthworks are also reduced to a minimum - only digging trenches to the house for laying pipes. And as a disadvantage, low accessibility for most homeowners can be noted simply due to the lack of water bodies in reasonable proximity to housing.
By the way, for the purpose of heat exchange, drains are often used - they have a fairly stabilized positive temperature even in cold weather.
D. Taking heat from the air
Heat for heating a home or for hot water supply can be taken literally from the air. Air-to-water heat pumps operate on this principle. air – air».
By and large, this is the same air conditioner, only switched to the “winter” mode. The efficiency of such a heating system depends very much on the climatic conditions of the region, and on the vagaries of the weather. Although modern installations are designed to operate even at very low temperatures (up to -25, and some even up to -40 ° FROM), but the energy conversion coefficient drops sharply, the profitability and expediency of such an approach immediately begin to raise a lot of questions.
But on the other hand, such a heat pump does not require any labor-intensive operations at all - most often its primary heat exchange unit is installed either on the wall (roof) of the building, or in its immediate vicinity. By the way, it is almost impossible to distinguish it from the external unit of a split air conditioning system.
Such heat pumps are often used as additional sources of thermal energy for heating, and in the summer as a heat generator for hot water supply.
The use of such heat pumps is fully justified for recovery - the use of secondary heat, for example, at the outlets of ventilation shafts (channels). Thus, the installation receives a fairly stable and high-temperature source of energy - this is widely used in industrial enterprises, where there are constantly sources of secondary heat for its disposal.
In air-to-air and air-to-water systems, there is no primary heat exchange circuit at all. The fans create an air stream that directly blows the evaporator tubes with the refrigerant circulating through them.
By the way, there is a whole line of heat pumps DX - type (from the English "direct exchange", which means "direct exchange"). In them, too, in fact, there is no primary circuit. Heat exchange with a source of low-grade heat (in wells or in layer of soil) passes immediately in copper pipes filled with refrigerant. On the one hand, this is more expensive and more difficult to implement, but it allows you to significantly reduce both the depth of the wells (one 30-meter vertical one or several inclined ones up to 15 m is enough), and the total area of the heat-exchange horizontal field, if it is located under the top layer of soil. Accordingly, we can talk about a greater conversion factor, and in general - the efficiency of the heat pump. But only copper heat exchange pipes are much more expensive than plastic ones and more difficult to install, and the cost of the refrigerant is much higher than that of a conventional antifreeze coolant.
And how is the air conditioner arranged, and can it be mounted independently?
It has already been said that basic principle the actions of the air conditioner and the heat pump are practically “twins”, but in a “mirror image”.
More about the device and the basic rules - in a special publication of the portal.
Video: useful information on the theory and practice of using heat pumps
General advantages and disadvantages of heat pumps
So, we can draw a certain line in the consideration of heat pumps, focusing on their main, imaginary and real, advantages and disadvantages.
BUT. High efficiency and overall profitability of this type of heating.
This has already been mentioned above - in a well-thought-out and properly installed system, under optimal operating conditions, you can count on receiving 4 kW of thermal energy instead of the spent 1 kW of electrical energy.
All this will be fair only if the housing has received the highest quality insulation. This, of course, applies to any heating systems, it’s just that these “magic numbers” of 300% show the importance of reliable thermal insulation to a greater extent.
In terms of regular costs for consumed energy resources, heat pumps are in first place in terms of efficiency, somewhat ahead of even cheap network gas. At the same time, one should also take into account the fact that there is no need to transport and store fuel reserves - if we are talking about stakes on solid or liquid fuel.
B. The heat pump can become highly economical main source of heating and hot water.
This issue has also already been touched upon. If the house is used as the main source of heating in the premises, then the heat pump of the appropriate power must “pull” such a load. For most of the usual radiators, a temperature of 50 ÷ 55 degrees will be clearly insufficient.
Special mention should be made of pumps that extract heat from the air. They are extremely sensitive to current weather conditions. Although manufacturers claim the possibility of working at -25 and even -40 ° FROM, efficiency drops sharply, and there can be no talk of any 300%.
A reasonable solution is to create a combined heating system (bivalent). As long as the HP has enough power, it acts as the main source of heat, in case of insufficient poweroffensive real cold weather - electric heating, liquid or solid fuel boiler, solar collector, etc. come to the rescue. Gas equipment is not considered in this case - if it is possible to use network gas for heating, then the need for a heat pump looks very doubtful, at least at the current level of energy prices.
AT. A heat pump heating system does not require a chimney. It works almost silently.
Indeed, the owners will not have any difficulties with the arrangement of the chimney. As for the silence of work, like any other household appliances with various drives, the noise background is still present - from the operation of the compressor, circulation pumps. Another question is that in modern models this noise level, with the correct debugging of the unit, is very small and does not cause concern to residents. In addition, probably, few people would think of installing such equipment in living rooms.
G. Full environmental friendliness of the system - there are no any emissions into the atmosphere, there is no threat to the residents of the house.
That's right, especially with regard to models in which modern freon, harmless to the ozone layer, is used as a refrigerant (for example, R-410A).
You can also immediately mark the fire - and explosion safety such a system - there are no flammable or combustible substances, the accumulation of their explosive concentrations is excluded.
D. Modern heat pumps are universal climate units capable of operating both for heating and air conditioning in the summer.
This is a very important advantage, which, indeed, gives the hosts a lot of additional amenities.
E. The operation of the heat pump is fully controlled by automation and does not require user intervention. Such a system, unlike others, does not need regular maintenance and preventive maintenance.
We can fully agree with the first statement, however, not forgetting to mention that most modern heating gas or electric installations are also fully automated, that is, not only heat pumps have this advantage.
But on the second question, you can enter into a discussion. Probably, none of the industrial or domestic heating units can do without regular checks and preventive maintenance. Even if it is fair to assume that it is not worth climbing into the internal circuit with a refrigerant and into automation, the external circuits with antifreeze or other coolant will still require some participation. Here and regular cleaning (especially in air systems), and monitoring the composition and level of the coolant, and auditing the operation of circulation pumps, and checking the condition of the pipes for integrity and the presence of leaks on the fittings, and much more - in a word, something that cannot be done without one heating system. In a word, the statement about the complete uselessness of maintenance looks, at least, unfounded.
AND. Fast payback of a heating system with a heat pump.
This question is so ambiguous that it deserves special attention.
Some companies involved in the implementation of such equipment promise their potential customers a very quick return on investment in the implementation of the project. They give calculations in tables, according to which, indeed, one can create an opinion that a heat pump is the only acceptable solution if it is not possible to stretch a gas main to the house.
Here is one such sample:
| Fuel types | Natural gas (methane) | Firewood chopped birch | Email energy at a single rate | Diesel fuel | Heat pump (night rate) |
|---|---|---|---|---|---|
| Unit fuel supplies | m³ | 3 m³ | kWh | liter | kWh |
| Fuel cost. with delivery, rub | 5.95 | 6000 | 3.61 | 36.75 | 0.98 |
| fuel calorie content | 38.2 | 4050 | 1 | 36 | 1 |
| Unit calorie measurements | MJ/m³ | kWh | kWh | MJ/liter | kWh |
| Boiler efficiency,% or COP | 92 | 65 | 99 | 85 | 450 |
| Fuel cost, rub/MJ | 0.17 | 0.41 | 1.01 | 1.19 | 0,06 |
| Fuel cost, rub/kW*h | 0.61 | 1.48 | 3.65 | 4.29 | 0.22 |
| Fuel cost, rub/Gcal | 708 | 1722 | 4238 | 4989 | 253 |
| Fuel cost per year, rub | 24350 | 59257 | 145859 | 171721 | 8711 |
| Service life of equipment, years | 10 | 10 | 10 | 10 | 15 |
| Approximate cost of equipment, rub | 50000 | 70000 | 40000 | 100000 | 320000 |
| Installation cost, rub | 70000 | 30000 | 30000 | 30000 | 80000 |
| The cost of connecting networks (technical conditions, equipment and installation), rub | 120000 | 0 | 650 | 0 | 0 |
| Initial investment, rub (approximately) | 240000 | 100000 | 70650 | 130000 | 400000 |
| Operating costs, rub/year | 1000 | 1000 | 0 | 5000 | 0 |
| Types of maintenance work | maintenance, camera cleaning | cleaning of the chamber, chimneys | Replacement of heating elements | chamber cleaning, injectors, filter replacement | No |
| Total expenses for the entire period of operation (including fuel costs), rub | 493502 | 702572 | 1529236 | 1897201 | 530667 |
| Total relative cost of 1 year of operation (fuel, depreciation, maintenance, etc.) | 49350 | 70257 | 152924 | 189720 | 35378 |
Yes, the final line is really impressive, but is everything “smooth” here?
The first thing that will catch the eye of an attentive reader is that the electricity tariff for electric heating is taken as a general one, and for a heat pump, for some reason, a reduced night rate. Apparently, in order to make the final difference more visual.
Further. The cost of heat pump equipment is shown not quite correctly. If you take a closer look at the offers on the Internet, then the prices for installations with a capacity of about 7 ÷ 10 kW, which can be used for heating purposes, start from 300 - 350 thousand rubles (air heat pumps and low-power installations used only for hot water supply cost somewhat smaller).
It would seem that everything is correct, but "the devil is in the details" This is only the cost of the hardware unit itself, which, without peripheral devices, circuits, probes, etc. - useless. The price of only one collector (without pipes) will give at least 12 ÷ 15 thousand more, a borehole probe costs no less. And if we add the cost of pipes, fittings, shut-off and fitting elements, a sufficiently large amount of coolant, the total amount grows rapidly.
Pipes, collectors, valves are also quite a “weighty” item of general expenses. But this is not all. It has already been mentioned that a heating system based on a heat pump, like probably no other, needs complex specialized calculations. When designing, a lot of factors are taken into account: the total area and volumes of the building itself, the degree of its insulation and the calculation of heat losses, the availability of a sufficient source of power supply, the presence of the necessary area of \u200b\u200bthe territory (nearby reservoir) for placing heat exchange horizontal circuits or drilling wells, the type and condition of soils , the location of aquifers and much more. Of course, both survey and design work will also require time and appropriate payment to specialists.
The installation of equipment “at random”, without proper design, is fraught with a sharp decrease in the efficiency of the system, and sometimes even local “environmental disasters” in the form of unacceptable hypothermia of the soil, wells or wells, reservoirs.
The next is the installation of equipment and the creation of heat exchange fields or wells. We have already mentioned the scale of earthworks, the depth of drilling. To fill the wells after the installation of the probes, a special concrete solution with a high degree of thermal conductivity is required. Plus to this - switching circuits, laying highways to the house, etc. - all this is another considerable "layer" of material costs. This also includes the purchase and installation of an accumulating tank with the necessary automatic control, alteration of the heating system for underfloor heating or the installation of special heat exchangers.
In a word, the costs are very impressive, and, probably, this is what keeps heating systems from heat pumps in the category of “exotics”, inaccessible to the vast majority of owners of private houses.
But what about their highest popularity and mass application in other countries? The fact is that government programs are working there to stimulate the population to use alternative sources of energy supply. Consumers who have expressed a desire to switch to these types of heating are eligible to receive government subsidies that largely cover the initial costs of designing and installing equipment. Yes, and the level of income of working citizens, to be honest, there a little higher than in our area.
For European cities and towns, this is a fairly familiar picture - a heat pump heat exchanger near the house Summary - statements about the quick payback of such a project should be treated with a certain degree of caution. Before undertaking such a large-scale and responsible set of measures, one should carefully calculate and weigh all the "accounting" to the smallest detail, assess the degree of risk, one's financial capabilities, planned profitability, etc. Perhaps there are more rational, acceptable options - laying gas, installing modern ones, using new developments in the field of electric heating, etc.
What is written should not be taken as a “negative” about heat pumps. Of course, this is an extremely progressive direction, and it has great prospects. The point is only that in such matters one should not show rash voluntarism - decisions should be based on carefully thought-out and comprehensively carried out calculations.
Prices for the range of heat pumps
Heat pumps
Is it possible to assemble a heat pump with your own hands?
The general prospect of using "gratuitous" sources of thermal energy, combined with the continuing high price of equipment, willy-nilly lead many home craftsmen to create such heating installations on their own. Is it possible to manufacture a heat pump with your own strength?
Of course, it is quite possible to assemble such a heat engine using some ready-made units and the necessary materials. On the Internet, you can find both videos and articles with successful examples. True, it is unlikely that it will be possible to find exact drawings, everything is usually limited to recommendations on the possibility of manufacturing certain parts and assemblies. However, there is a rational “grain” in this: as already mentioned, a heat pump is such an individual system that requires calculations in relation to specific conditions that it will hardly be advisable to blindly copy other people's developments.
Nevertheless, those who nevertheless decide on independent production should heed some technological recommendations.
So, let's "bracket" the creation of external circuits - heating and primary heat exchange. The main task in this case is the manufacture of two heat exchangers, an evaporator and a condenser, connected by a copper tube circuit with a refrigerant circulating through it. This circuit, as can be seen from the circuit diagram, is connected to the compressor.
The compressor is easy to find - new or from equipment disassembled for spare parts The compressor itself is not so difficult to get - it can be purchased new - in a specialized store. You can search in the household market - they often sell units from old refrigerators or air conditioners disassembled for parts. It is quite possible that the compressor will be found in their own stocks - many zealous owners do not throw away such things even when buying new household appliances.
Now - the question of heat exchangers. There are several different options here:
BUT. If it is possible to purchase finished plate heat exchangers , sealed in a sealed case, then a lot of problems will be solved immediately. Such devices have excellent heat transfer efficiency from one circuit to another - it is not without reason that they are used in heating systems when connecting autonomous intra-apartment wiring to the pipes of the central network.
Convenience is also in the fact that such heat exchangers are compact, have ready-made pipes, fittings or threaded connections for connection to both circuits.
Video: making a heat pump using ready-made heat exchangers
B. Heat pump version with heat exchangers made of copper tubes and closed tanks.
Both heat exchangers, in principle, are similar in design, but different containers can be used for them.
A cylindrical stainless steel tank with a capacity of about 100 liters is suitable for the condenser. It is necessary to place a copper coil in it, bringing its ends from above and below to the outside and hermetically sealing the passage points at the end of the assembly. The inlet must be located at the bottom, the outlet, respectively, at the top of the heat exchanger.
The coil itself is wound from a copper tube, which can be purchased at the store with a footage (wall thickness - at least 1 mm). As a template, you can take a large diameter pipe. The coils of the coil should be somewhat spaced apart, attaching, for example, to a perforated aluminum profile.
The heating water circuit can be connected by means of ordinary water pipes mounted (welded, soldered or screwed with a seal) at opposite ends of the heat exchange tank. The internal space of the heat exchanger is used for water circulation. The end result should be something like this:
For an evaporator, such difficulties are not needed - there are no high temperatures or excess pressure, so a voluminous plastic container will suffice. The coil winds in much the same way, its ends are brought out. Conventional plumbing connections are also sufficient to circulate water from the primary circuit.
The evaporator is also installed on brackets next to the condenser, and near them a platform is being prepared for mounting the compressor with its subsequent connection to the circuit.
Recommendations for piping the compressor, installing a throttle control valve, the diameter and length of the capillary tube, the need for a regeneration heat exchanger and etc.., will not be given - this should only be calculated and installed by a refrigeration specialist.
It should be remembered that it requires high skills in hermetic soldering of copper pipelines, the ability to properly pump refrigerant - freon, carry out checks and carry out a test run. In addition, this work is quite dangerous, requiring the observance of very specific precautionary rules.
AT. Heat pump with pipe heat exchangers
Another option for manufacturing heat exchangers. To do this, you will need metal-plastic and copper pipes.
Copper tubes are selected in two diameters - about 8 mm for the condenser, and about 5 ÷ 6 for the evaporator. Their length is respectively 12 and 10 meters.
Metal-plastic pipes are designed to circulate water through them from the primary heat exchange and heating circuits, and copper pipes of the heat pump's internal circuit will be located in their cavity. Accordingly, the diameter of the pipes can be taken 20 and 16 mm.
Metal-plastic pipes are stretched in length so that copper pipes can be inserted into them without much effort, which should protrude about 200 mm on each side.
A tee is put on and “packed” on each end of the pipe, so that the copper tube passes straight through it. The space between it and the body of the tee is securely sealed with a heat-resistant sealant. The remaining perpendicular outlet of the tee will serve to connect the heat exchanger to the water circuit.
Pipes are assembled in spirals. Be sure to immediately provide for their thermal insulation by wearing foam rubber insulating "shirts". The result is two finished heat exchangers.
You can place them one above the other in an impromptu frame-type case. On the same frame, a platform for installing the compressor is also provided. And in order to reduce the transmission of vibration from it to the overall structure, the compressor can be mounted, for example, through automotive silent blocks.
To carry out the piping of the compressor and refueling the resulting circuit with freon, again, you will need to invite a refrigeration specialist.
You can install such a heat pump in its intended place and connect the tee fittings on the heat exchangers, each to its own circuit. It remains only to supply power and start the unit.
All considered home-made heat pumps are quite workable designs. However, one should not assume that it is so easy to completely solve the problem of cheap home heating. Here we are talking, rather, about the creation of existing models that require further refinement and modernization. Even experienced craftsmen who have already made more than one similar device are constantly looking for ways to improve, creating new “versions”.
Video: how the master improves his own heat pump
In addition, only the heat pump itself was considered, and for normal operation it requires control, monitoring, and adjustment equipment associated with the home heating system. Here you can no longer do without certain knowledge in the field of electrical engineering and electronics.
Again, we can return to the problems of calculations - will a home-made heat pump “pull” the heating system so as to become a real alternative to other heat sources? Often in these matters, home craftsmen have to "wander by touch." However, if the basic principle is mastered, and the first model is successfully earned, this is already a big victory. You can temporarily adapt your test sample to provide the house with hot water for domestic purposes, and start designing a more advanced unit yourself, taking into account the experience already gained and correcting the mistakes made.
Hot water supply - from the energy of the sun!
A very practical solution would be to use the energy of the sun's rays to provide domestic hot water. This source of alternative energy is much simpler and cheaper than a heat pump. How to do it - in a special publication of our portal.
