How to make a heat pump out of a refrigerator. Do-it-yourself heat pump working options for the overflow scheme. Do-it-yourself water-to-water heat pump from an air conditioning compressor

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 on every suburban area, and for operation ground water need to get permission. 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. Soldered into the shell threaded connections to connect to the loop. After that, parts of the tank can be welded.
For the 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 correct operation pump, this calculation is best entrusted to a heating engineer. He will be able to finally connect the installation and set up the compressor.
It remains only to add 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 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

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. Note that the natural gas pipe low pressure passes 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 power supply 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, circuit diagram:

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:

Compressor on R22 freon, which means a slightly higher coefficient useful action. 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 a piston one ... (It looks a little oval and the engine winding dangles 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 coil heat exchange area. 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:

No evaporator required high temperature, and I chose a plastic container like a 127 liter barrel with a wide mouth.

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. 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. Water supply and drainage 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. Better to use 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, but a regular one for 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 room temperature about +15s.

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

Would you think that a device based on the technology of an ordinary refrigerator would be able to provide high-quality heating not only for the pool, but for the whole house? All this is performed by a conventional heat pump, which, moreover, can be made independently at home.

If you understand the principles of its operation and design features, you can cope with its creation yourself. Which is very useful and convenient for arranging your living space.

1 Working principle

The underlying technology, in essence, is not much different from the technology for the operation of a conventional refrigerator. As you know, a refrigerator pumps heat out of the chambers to ensure a low temperature and transfers it outside through radiators.

The technology of a heat pump is also based on the same principle: for space heating, it “pumps out” heat from the ground or water, processes it and gives it to the heating system of a house, greenhouse or pool.

The refrigerant (freon or ammonia) circulates through a system consisting of an internal and outer contour. The external circuit is located in the heat intake environment. This medium can be air, earth, or water.

In fact, any natural environment has a sufficient amount of dissipated thermal energy, which is collected by the refrigerant and transferred to the system for processing. To start the processes, it is necessary that the heat exchanger raise its temperature by 4-5 degrees. This is very important point, since the heat exchanger directly affects all conditions around.

Further, from the external circuit, the heated refrigerant enters the internal circuit. The first block, the evaporator, transforms the heat exchanger from a liquid state into a gas form. This is possible due to the fact that freon, at a low pressure of the external environment, has a very low boiling point.

Further, from the evaporator, freon in gaseous form enters the compressor, where the gas is compressed, as a result of which its temperature rises sharply. After that, the gas enters the third block - the condenser. In it, the gas gives up its temperature to the water - the heat carrier of the heating system of the house, after cooling it returns to a liquid form, and re-circulation is performed.

The main characteristic of the productivity of a heat pump for heating is the conversion factor, which depends on the ratio of the heat output produced by the pump to the amount of heat energy consumed.

1.1 How does a heat pump work?

The design of classical heat pumps is divided into two main circuits - external and internal. The heat exchanger plays a very important role in them, as the main provoking factor. The external circuit consists of pipes through which the heat exchanger (refrigerant) circulates.

Such a circuit may different ways implementation and location, however, it always performs only one function - to circulate the refrigerant in the heat intake environment, and move the heat exchanger to the compressor. Pipes of the outer contour are made of plastic or other materials with high thermal conductivity.

The external circuit - the pump itself, consists of a condenser, compressor, evaporator and pressure reducing valve.

In addition, a hydrodynamic HP is distinguished, the design of which differs from a conventional heat pump for heating. The hydrodynamic pump consists of a power unit (engine), a heat generator, and a coupling that transfers the energy generated by the drive to the generator, where the heating fluid is heated.

1.2 Types of units and their differences

Depending on the type of environment in which the heat pump draws energy, the following types of HP are distinguished:

Air-water;

An air source heat pump is the most budgetary option for alternative heating; it can be equipped with your own hands, since for its operation there is no need to equip a complex external circuit system.

However, the air pump has one significant drawback, which makes its use in our climate unjustified - with a decrease in air temperature, its efficiency sharply decreases.

If you want to make a heat pump with your own hands for heating the pool, - the best option. Moreover, for the pool, this option will be preferable, since it is quite easy to work with it and it is extremely practical.

Water-water;

The external contour for heat intake is located in a non-freezing reservoir - artificial or natural. In terms of heat transfer, water is the most efficient medium. In practice, the use of surface water bodies is not justified, as they freeze during the cold season.

Maximum stability and efficiency of heating with a heat pump is achieved by using groundwater. For this, special wells are created in which the external contour of the system is located.

Despite the fact that this heating technology is the most labor-intensive, its use makes sense, since the temperature of groundwater does not undergo significant changes at different times of the year. The best option for heating the pool or small residential premises.

Brine-water;

Soil is used for heat intake, which necessitates the creation of collectors (for horizontal placement of pipes of the external contour), or shallow wells (for vertical placement - 1 running meter well gives 40-60 watts of heat).

This option is used everywhere - from warming up the pool, to heating the whole house. The technology got its name "brine" from the fact that a special non-freezing liquid is poured into the pipes.

There is also a Frenette heat pump - it works on a different technology, and has nothing in common with conventional heat pumps. This pump consists of two cylindrical containers - a larger one and a smaller one, while the smaller container is placed inside a large vessel.

The free space between them is filled with oil. The outer cylinder is fixedly fixed, and the inner container is connected to the drive shaft, during which, due to the friction forces arising from the rotational movements of the cylinders, the oil is heated to a very high temperature and transferred to the heating radiators.

Such a mechanism has enough high efficiency, and at the same time, it can be easily made by hand.

2 How to make and install a heat pump with your own hands?

It is quite possible to make a heat pump with your own hands, but for this you need to find a good compressor.

You can do this by visiting some local repairman household appliances where, having gutted an old air conditioner, you will get a quite high-quality compressor for a small amount (their service life is much longer than the average life of air conditioners).

As a condenser, you can use a stainless steel tank, approximately 100 liters. And for the circuit through which the heat exchanger will circulate, thin copper plumbing pipes are perfect.

DIY heat pump - manufacturing steps:

To make a Frenette heat pump with our own hands, we need to acquire the following materials:

Steel cylinder (select the diameter based on the pump power that you need for heating: the larger the working surface, the more efficient the device will be);
Steel discs, with a diameter of 5-10% less than the diameter of the cylinder;
Electric motor (it is best to initially select a drive with an elongated shaft, since disks will be installed on it);
Heat exchanger - any technical oil.

The number of revolutions that the engine can produce will determine the temperature to which the Frenette pump can heat water for heating a house or a pool. In order for the water in the radiators to warm up to 100 degrees, it is necessary that the drive provide 7500-8000 rpm.

The shaft of the power unit on bearings is placed inside the steel cylinder. The place where the shaft enters the cylinder must be securely sealed, since the presence of even the slightest vibration quickly disables the mechanism.

Work disks are mounted on the motor shaft. The required distance between them can be set by screwing the nuts after each disk. The number of disks is determined depending on the length of the cylinder - they must evenly fill its entire volume.

We drill two holes in the upper and lower parts of the cylinder: heating pipes will be connected to the upper one, into which oil will be supplied, and a return pipe is connected to the lower hole to return the used oil from the radiators.

The whole structure is fixed on a metal frame. After the unit is assembled, the cylinder is filled with oil, the pipes of the heating main are connected to it and the connections are sealed.

The Frenetta heat pump has a very high efficiency, which allows it to be effectively used in any heating systems. It can be used to heat any utility rooms, garages, and residential buildings. In addition, due to its compact size, such a home-made pump is great for heating a pool or a “warm floor”.

But remember that when heating the pool and other large water containers, you need a pump of sufficient power, otherwise you will simply use it for other purposes and you will not get the desired results.

2.1 Installation of heating units

Features of installation of heat pumps depend, first of all, on the method of placement of the external circuit.

. For a vertical mounting method, they are created with a depth of 50 to 100 meters, into which a special probe is lowered. For horizontal laying, a trench is created for the same length or a pit in which the pipes are laid parallel to each other. Pipes are laid in the ground to a depth of one and a half meters.
Water-to-water pumps: the external circuit is laid on the bottom of the reservoir and led to the heat pump.
Air-to-water: the unit with pipes of the external circuit is installed on the roof or on the wall of the building (according to appearance it is difficult to distinguish it from the outdoor box of the air conditioner) and is connected to the heat pump indoors.

2.2 An example of a homemade Frenette unit (video)

Unlike alternative energy devices such as solar panels and wind turbines, the heat pump is less well known.

And in vain. The most common "soil-water" scheme works stably and does not depend on weather or climatic features. And you can make it yourself.

A bit of theory

It is easiest to use the natural heat of the earth to heat your home if there are geothermal waters in the region (as they do in Iceland). But such conditions are very rare.

And at the same time, thermal energy is everywhere - you just need to extract it and make it work. This is what a heat pump is for. What does it do:

takes energy from low-temperature natural sources;
accumulates it, that is, raises the temperature to high values;
gives it to the coolant of the heating system.

In principle, the standard scheme of a compressor refrigerator is used, but “vice versa”. Natural coolant circulates in the primary circuit. It is closed to a heat exchanger that acts as an evaporator for the second circuit.

1 - earth; 2 - brine circulation; 3- circulation pump; 4 - evaporator; 5 - compressor; 6 - capacitor; 7 - heating system; 8 - refrigerant; 9 - throttle

The second circuit is the heat pump itself, inside of which there is freon. The heat pump cycle consists of the following steps:

In the evaporator, freon is heated to the boiling point. It depends on the type of freon and the pressure in this part of the system (usually up to 5 atmospheres).
In a gaseous state, freon enters the compressor and is compressed to 25 atmospheres, while its temperature rises (the greater the compression, the higher the temperature). This is the phase of heat accumulation - from a large volume with a low temperature, a transition to a small volume with a high temperature.
The pressurized gas enters the condenser, in which heat is transferred to the heat carrier of the heating system.
After cooling, freon enters the throttle (aka flow regulator or expansion valve). In it, the pressure drops, freon condenses and returns to the evaporator as a liquid.

Where is the best place to "take away" heat

In principle, there are three environments from which heat can be “taken away”:

1. Air. At normal pressure, all types of freons boil at negative temperatures(e.g. R22 - approx. -25 °C, R404 and R502 - approx. -30 °C). But for circulation in the system, it is necessary to create excess pressure already in the first phase - evaporation. The same 4 atmospheres in the evaporator requires that the outdoor air temperature be at least 0 °C for R22 and -5 °C for R404 and R502. In our regions, this type of heat pump can be used for heating in the off-season and for hot water in the warm season.

2. Water. This is a more stable source of heat, provided that the reservoir does not freeze to the bottom in winter. But the house should not just be located next to a lake or river, but be on the first line.

3. Earth. The most stable source of thermal energy. Two schemes can be used - horizontal and vertical. Horizontal seems easier because it does not require drilling. But you have to do a lot earthworks digging a system of trenches to a depth below the level of soil freezing (for middle latitudes, it ranges from 1 meter in the west of the European part of the country to 1.6–1.8 closer to the Urals, in Siberia the situation is “even worse.” The vertical scheme is more universal and effective, but requires drilling to a considerable depth, although several shallow wells can be used instead of one deep well.

circuit diagram

The heat pump circuit itself is simple: evaporator - compressor - condenser - throttle - evaporator.

The "heart" of the circuit is the compressor. You can buy a new one, but it's cheaper to find a used one. Naturally, we are not talking about low-power compressors for household refrigerators, but about models installed in split systems. It is necessary to focus not on the power consumption, but on the power in heating mode (which is 5–20% higher than in cooling mode).

The compressor model is selected according to the ratio of 1 kW per 10 square meters. meters of heated area.

Attention! Power can be indicated not only in kW, but also in BTU ( English unit measurement of thermal energy, adopted for climate technology). Recalculation is easy to do - divide the value in BTU by 3.4.

When calculating the parameters of the heat pump, including heat exchangers, use software, intended for modeling, calculations and optimization of cooling systems, for example, CoolPack

Already at the stage of calculations (more precisely, when setting the "introductory"), you can optimize the system by choosing the optimal thermal conditions.

The use of a heat pump is effective for low-temperature heating systems, for example, for underfloor heating with a temperature not exceeding 35–40 °C. By the way, the same temperature is recommended for medical requirements for the DHW system.

For each type of freon there is optimal temperatures"input" and "output", more precisely, boiling and condensation, but the difference in all of them is no more than 45-50 ° C.

It would seem that increasing the temperature at the outlet of the heat pump will have a positive effect, but this is not so. The temperature difference will also increase, which will lead to a decrease in COP (coefficient of conversion, or efficiency of a heat engine). In addition, this will require the use of a more powerful compressor and additional power consumption.

The ideal COP cannot be achieved (losses in the compressor, power consumption, heat losses during transportation within the system, etc.), so real values usually lie between 3 and 5.

There is another way to increase efficiency - the use of a bivalent heating scheme.

In reality, the operation of the heating system at full capacity is needed only for 15–20% of the entire season. During this time, you can use additional heating devices (for example, a ceramic heater or a convector). Reducing the calculated heat output to 80% will save on the compressor, reduce the depth of the well or the length of the pipes of the horizontal circuit, and reduce the energy consumption for servicing the heat pump itself.

The design of a horizontal or vertical ground heat exchanger depends on the given nominal power of the heat pump and the COP. On average, 20 W are removed from each meter of the "horizon" (with a pipe laying step of at least 0.7 m), and from the "vertical" - 50 W. But specific values depends on the type of rock and its moisture content. Groundwater has the best values.

Interesting! There are other ground heat exchangers - "spiral" or "basket". In fact, this is a vertical probe from a pipe in the form of a spiral, which allows to reduce the depth of drilling.

After determining the length of the horizontal loop or the depth of the vertical probe, the dimensions of the evaporator and condenser are calculated.

Manufacturing of the evaporator and condenser

You can buy ready-made heat exchangers for both the evaporator (for low pressure) and for the condenser (with pressure up to 25 bar). But it is cheaper to make them from a copper tube for air conditioners (which is designed specifically to work with refrigerants at high pressure) and improvised containers.

Important! Plumbing copper pipe is not as "clean" and flexible. It is worse to solder and roll during installation.

The surface area of the heat exchanger is calculated, which is directly proportional to the heat release power and inversely proportional to the temperature difference of the heat carriers at the inlet and outlet of each connected circuit (ground and heating systems).

Knowing the pipe diameter and surface area, determine the length of each coil for the evaporator and condenser.

It is better to make a container for a condenser from stainless steel (the temperature of the incoming freon vapor can be quite high):

take a ready-made tank of a suitable capacity (to fit a spiral of copper tube);
place a coil in it (inlet at the top, outlet at the bottom);
bring out the ends of the copper tube for connection to the compressor and expansion valve (by soldering or flange);
make adapters in the tank for connecting pipes of the heating system;
seal the lid.

The evaporator operates at lower temperatures, so you can take a cheaper one for it plastic container, into which adapters are cut for connection to the ground circuit. It also differs from the condenser in the location of the heat exchanger coil - the inlet (liquid phase of freon from the expansion valve) from below, the outlet to the compressor from above.

Circuit mounting

After the manufacture of heat exchangers, the gas-hydraulic circuit is assembled:

install the compressor, condenser and evaporator in place;
solder or flange copper pipes;
connect the evaporator to the ground circuit pump;
connect the condenser to the heating system.

1 - circulation pump of the soil circuit; 2 - evaporator; 3 - exit of the soil circuit; 4 - thermostatic valve; 5 - compressor; 6 - to the heating system; 7 - capacitor; 8 - heating system return

The electrical circuit (compressor, ground loop pump, emergency automation) must be connected via a dedicated circuit, which must withstand fairly high starting currents.

It is obligatory to use a circuit breaker, as well as an emergency shutdown from the temperature switch: at the water outlet from the condenser (in case of overheating) and the brine outlet from the evaporator (in case of subcooling).

In recent decades, homeowners have a fairly large selection of heating systems. It is no longer necessary to connect to centralized networks and use traditional sources. You can choose equipment that runs on alternative energy, but its main drawback is the high cost. Do you agree?

However, if you build a heat pump with your own hands from an old refrigerator, the system can be significantly reduced in price. And we will tell you how to do it.

In this article, we have selected the most simple solutions and provided them with detailed drawings and diagrams. Therefore, for a home craftsman to understand them is not difficult. In addition, here you will find step by step instructions for the manufacture of heating equipment. And the posted videos will tell about design features heat pump and the features of its connection.

Theoretically, any person has a large selection of energy sources. In addition to natural gas, electricity, coal, it is also wind, sun, temperature difference between land and air, land and water.

In practice, the choice is limited, because everything rests on the cost of equipment and its maintenance, as well as the stability of operation and the payback period of installations.

Each of the energy sources has both advantages and serious disadvantages that limit its use.

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