For heating and providing hot water to private homes, it is advisable to use a water-to-water heat pump powered by natural sources - groundwater, rivers, reservoirs, etc. The system is absolutely environmentally safe and does not require regular costs for consumables, which is why it is becoming increasingly in demand.
We will talk about options for a heat pump that uses eco-energy from water to transfer it to household heating systems. For inquisitive home craftsmen, we have described the operating principles of popular device options and construction technology. Here you will find out what equipment is required for the system to operate.
Operating principle of a water-to-water heat pump
The heat pump embodies the principle of the Carnot cycle. It lies in the fact that a substance moving through a closed system and changing its state of aggregation from liquid to gaseous under the influence of chemical, physical or thermal factors releases and absorbs a huge amount of thermal energy.
The working substance is a thermal carrier - water from a well or reservoir.
Even in winter, natural springs at a certain depth maintain a positive temperature, so thermal energy can be extracted from them all year round. The only drawback of the installation is the high power consumption and the need to purchase additional equipment.
The diagram shows the circulation path of water and refrigerant. The system allows you to receive thermal energy, regardless of the season
The main elements of a water-to-water heat pump:
- compressor;
- evaporator;
- capacitor;
- expansion induction valve;
- automatic system that monitors indicators;
- multiple lines of copper pipes;
- working substance (refrigerant).
Using a special pump, water flows through tubes from the source to the heating unit, after which it interacts with gas (freon), which boils at a temperature of +2-3 degrees. Freon absorbs some of the heat from the water and is sucked into the compressor, where its temperature rises during compression.
Heat pump equipment takes up a lot of space, but provides an opportunity to get rid of utility dependence
Next, the refrigerant enters the condenser, after which the hot substance heats the water to a given temperature (from +40 to +80 degrees), which is transported through the pipes of the heating system.
Cooled water enters the evaporator and then drains into the receiving well. After passing through the condenser, the refrigerant becomes liquid and collects at the bottom of the element, then returns through the throttle to its original location. Then the cycle repeats.
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The essence of the water-to-water heat pump
Geothermal system indoor unit
Compact heat pump for a private home
Economical heating arrangement
Useful tips
At all stages of building a house, starting from the design stage, we must remember that the HP is an inertial system. It can be compared to a massive Russian stove, which was usually heated once a day during cooking. Then the accumulated heat warmed the home until the next morning.
Walls made of heavy logs have a fairly high degree of thermal inertia. Simply put, they cool down slowly when it gets colder at night. Good thermal inertia for thick stone walls, as well as for heavy concrete or brick.
Polystyrene foam and foam concrete have good thermal insulation properties. But due to their low specific gravity they have low thermal inertia. A heater in a building with walls made of such materials, when the outside air temperature sharply drops, will not always be able to “pump” enough heat from outside into the “warm floor” heating system.
Other factors must also be taken into account:
- To reduce heat loss or avoid freezing of pipes in the main between the house and the wells or collector, it is necessary to lay them to a depth below the freezing level. In Crimea - 0.75 meters is enough, and at the latitude of Moscow - at least 1.5.
- The greatest heat loss is usually through windows. Therefore, triple glazing is not a luxury at all, but an economically sound construction solution. The ideal option is to use glass that can reflect infrared rays.
- In the case of using the option of 2 wells for collecting and draining water, the distance between them must be at least 20 meters.
- It is better to try a homemade TN first in a utility room or garage. Installing heated floors in a residential area will require additional costs. Find out the order of the corner fireplace by following the link.
What to look for when arranging such heating?
There are a large number of different modifications of heat pumps designed for premises of any purpose and size, as well as operating in different conditions. The equipment is intended for heating houses with a total area of 50 to 150 square meters.
Guideline No. 1 - water hardness
The water quality of a well or reservoir plays an important role when choosing equipment. Not all models are able to work on hard water containing large amounts of manganese and iron.
A high concentration of these elements harms the system - corrosion forms on the pipes faster, which leads to a decrease in the efficiency of the equipment and its service life.
Therefore, before purchasing a heat pump, they take a water sample and analyze it for the presence of these and other microelements - hydrogen sulfide, ammonia, chlorine, etc. Usually, if the temperature in the pond exceeds +13 degrees, then there is a high probability that there are a lot of iron and manganese ions in the water.
Thus, the water-to-water heat pump is selected taking into account the water hardness. There are systems whose elements are maximally protected from corrosion, but they are more expensive.
Guideline No. 2 - operating mode
The heat pump can be used as the sole heat source or in conjunction with other systems. Therefore, before choosing a model, it is important to determine in which mode the device will operate.
There are two types of system operation:
- Monovalent. The devices have great power and are suitable for heating a home.
- Bivalent. Less efficient devices complement the main heating equipment.
To build an autonomous system with a main water-to-water heating unit, you need a monovalent type.
Guideline No. 3 - pump power
Power is an important indicator when choosing a heat pump, since the performance of the system depends on it. The higher the power, the higher the efficiency of the equipment, but the higher the energy consumption.
The performance of the water-to-water heat pump is selected based on real needs
If you choose a device with insufficient power, the efficiency of the system will decrease if the heat loss in the house exceeds the amount of energy supplied by the system. The heat pump can operate around the clock, but it will have no effect due to the drop in water temperature.
When the heat loss of a building is lower than the heat transfer of the system, the pump usually automatically starts for a few minutes, heats the water to the set temperature, and transports it through the system. Then it turns off until the temperature drops a few degrees. Then the cycle repeats.
Guideline No. 4 - functionality of a specific model
Heat pumps may have additional functions, these are:
- An automatic control system that will allow you to adjust the microclimate of the room to your taste. Control is usually carried out using a remote control.
- Water heating function for hot water supply.
- Soundproof housing.
- Possibility of connection to other heating systems, solar collectors, which will make the heating equipment completely autonomous.
The service life of water-to-water heat pumps usually exceeds 30 years.
Equally important when choosing equipment is the cost of installation and assembly.
Efficiency
Over time, the profitability of HP becomes more and more obvious due to the constant increase in the cost of energy resources. Technology also does not stand still.
Programmable control circuits for home appliances with remote access no longer surprise anyone. The heat pump is seamlessly integrated into the smart home system, which reduces equipment wear and extends its service life.
A properly selected and high-quality installed heat pump is a guarantee of providing heat regardless of the time of year and market fluctuations in energy prices.
But a heat pump can achieve maximum efficiency if you decide on the choice of heating system at the early stages of building design. Then it is possible to choose the optimal materials and thickness of enclosing structures with the required thermal conductivity and thermal inertia.
Calculation of the required heat pump power
Before purchasing a system, it is important to first draw up a project and calculate the required equipment power. Productivity is calculated taking into account the actual needs for thermal energy. Heat consumption, heat loss at home and the presence or absence of a DHW circuit are taken into account.
Calculation algorithm:
- We calculate the total area of heated premises.
- We determine the required amount of energy for heating. The optimal indicator per 1 square meter is 0.07 kW.
- To heat a house of N square meters, you will need N*0.07 kW.
- For hot water supply, an additional 15-20% is added to the resulting number, that is, N*0.07*0.85 or N*0.07*0.80.
This calculation will be optimal for rooms with ceilings not exceeding a height of 2.7 m. More accurate calculations will be made by specialists during the preparation of the project.
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Interior of a water-to-water heat pump
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Efficient equipment with economical energy consumption
Heat pump heat exchanger in the hallway
Review of manufacturers
Installation costs, taking into account the cost of wells, can range from 5 to 10 thousand dollars. When using an open reservoir it will be 1.5-2 times cheaper.
Manufacturers of heat pumps are divided into three price categories:
- Cheap Chinese ones. For example, Meeting (China), maximum power - 7 kW, heated area - 50-100 m2, price - 95,200 rubles.
- They are produced under the American brand in China. For example, Mammoth (USA/China), maximum power - 7.8 kW, heated area - 50 m2, price - 261,000 rubles.
- The most expensive ones are traditionally German. For example, Stiebel Eltron (Germany), maximum power - 9.9 kW, heated area - 50 m2, price - 645,000 rubles.
It is recommended to choose an operator that provides a full range of services:
- design;
- supply;
- installation;
- commissioning works;
- service maintenance.
Prices for different heat pump models
Heat pump
Preparatory work before operation
Preparation for assembly, connection and commissioning of a heat pump from the water-to-water series includes a number of standard steps, which we will get acquainted with later.
Choosing the optimal water source
It should be noted that not every open source or water well is suitable for the uninterrupted operation of a heat pump. Water quality plays an important role, but filters will help solve the problem of contamination.
It is permissible to use a reservoir or pond located within a radius of 100 meters from the building. If there is no such source, then the need to drill wells arises.
The choice of source for a heat pump should be based on ease of use and cost of use. If there is a nearby open reservoir, it is wiser to use it
The behavior of an open source is more predictable than groundwater, so if possible, it is better to give preference to reservoirs.
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Geothermal well for heat pump
Inexpensive heat pump evaporator option
Connecting the evaporator pipes to the heat exchanger
Evaporator pipes are prepared for inspection
Installation of a thermal system using a well
To install a system using a heat pump, you will need two wells. One of the wells is usually called debit. It is into this that a special pump is immersed, with the help of which water is taken for subsequent processing in the system. The second well is a receiving well. Cooled water is drained into it.
The drain and supply wells must be located at least 15 meters apart from each other.
The depth of the debit well should not exceed 50 meters. The deeper the water source is, the more powerful the pump required to supply it, which will increase the amount of energy consumed.
Construction of a debit well
Before starting to operate a debit well, it is important to find out how much water it can produce and how much liquid is needed to provide heat to the entire room. The higher the water temperature, the less it will be needed for heating.
It is important to pre-calculate the volume V that needs to be pumped out of the well within an hour to heat the room. Let's say there is a pump whose heat output is equal to a certain number Q kW, and the power consumption is equal to a number P kW. You will also need to find out the temperature of the groundwater ( t1 ) and its temperature after temperature exchange ( t2 ).
Then the formula for calculating the volume of the required amount of water per hour looks like this:
V = (QP)/(t1-t2).
It is analytically impossible to determine the ability of a debit well to produce the required volume of water, so it is tested. For 3 days, the pump uninterruptedly pumps water from the well. In this way, the receiving well is also checked for its ability to receive the required amount of water under high load.
It is important to understand that groundwater behaves unpredictably, so the amount of water from a debit well may become less over time. For example, in spring there are high tides, but in winter, on the contrary, the water decreases. If there is not enough water in the well, the system automatically turns off and heating does not occur.
Features of the receiving well
The receiving tube well is located downstream of the groundwater. It is analytically impossible to determine in which direction the water is moving. Therefore, in practice, an arbitrary well is selected as a debit well and a submersible pump is launched into it.
If the water level does not drop during operation of the system, then the choice was made correctly. If the level has dropped and the water temperature has dropped, then it is necessary to swap the wells - move the submersible pump to another hole.
The drain pipe into the receiving well must be immersed a few centimeters in water, without reaching the bottom. If you dump waste liquid from above, it will lead to waterlogging. The tube well may stop receiving water and become clogged.
The result threatens overflow, and in winter, possible icing. The best options for a receiving source are a river or pond. If these objects are not nearby, then there is a need to drill one or more receiving wells in order to insure against overflow.
The figure shows an example of using one well as a receiving and debiting well
It is impossible to find out whether a well will receive water either analytically or by testing. Practice shows that a drain well can uninterruptedly absorb water for many years, or it can completely fail in one season.
There are technologies that allow you to use one well as a debit and a receiving well, but this method is not effective - operation will be accompanied by difficulties, a decrease in water temperature, waterlogging and a number of other problems are possible.
Design of a system using a reservoir
The selected pond must be deep enough so that the lower layers of water do not freeze during severe frosts. In the Southern regions, the optimal depth will be approximately 1 meter; in the Northern regions, a source with a depth of 3 meters will be required. Also, the pond must be stable - fluctuations in the water level and its decrease are unacceptable.
There are two pipelines to the reservoir - debit and receiving. A submersible pump is installed in the receiving area
It is recommended to use HDPE models as pipes, which are characterized by durability and reliability. It is important to protect pipes from freezing by additionally insulating them, and from breakthroughs.
Preparing your home for a heat pump installation
To interact with a water-to-water heat pump, the house must be equipped with a water-based heating system, presented in the form of pipes and radiator batteries. For better insulation, it is also permissible to install heating pipes in the floor and walls.
If the equipment will be used to supply hot water, then the house must have a collection system. To operate the pump, you need to be connected to an electrical network with unlimited power.
Without additional measures for thermal insulation of the house (insulation from the outside, installation of double-chamber windows, etc.), operating a heat pump makes no sense.
Experts recommend additionally installing a supply-type ventilation system with an air heating mechanism. The freon used in the equipment is harmful to humans. If micro-ruptures occur in the system circuit, the gas will be released and thereby displace air from the room. The refrigerant can cause exacerbation of lung diseases and asthma attacks in humans.
A heat pump is heavy equipment, its weight can reach a ton (depending on the power and size), so in some cases its installation requires the construction of its own foundation, not connected to the foundation of the cottage.
Before installing the equipment, you need to take into account the permissible dimensions of the room and maintain the distance to the walls specified in the product passport.
Submersible pump for well
If a well produces much more water than needed, this does not mean that the pump needs to be more powerful. Let's take it in order.
On the one hand, it’s good that a well for a heat pump can also be used for domestic needs. But will it always be comfortable? You open the tap, water flows out of it with normal pressure, then the pump turns on and a sharp drop in pressure occurs. We doubt that this will suit anyone. The first thought is to replace the pump with a more powerful one. But this design also consumes more. For domestic needs, a submersible pump can work for 1-2 hours per day, but it is many times longer, or it can work with a heat pump for days, and accordingly consume more. Let's say we have calculated that we need a submersible pump of a certain model that satisfies us in terms of the required volume, taking into account the depth of the well and the duration of the line. In this case, such a pump consumes 500 watts, and in order to use water for domestic needs, it needs to be replaced with a pump with a power of 1 kW. Such a device will consume this kilowatt both when operating only the heat pump, and when simultaneously operating together with water consumption for domestic needs. Higher consumption by the submersible pump will result in a lower conversion ratio.
Let's take the example of a 12kW heat pump's consumption, which is about 2.7kW
2,7+0,5=3,2
2,7+1,0=3,7
12/3,2=3,75
12/3,7=3,25
In the first case, we will receive more heat per kilowatt of energy expended than in the second.
Let's do one more calculation. Let's assume that a heat pump is installed in Krasnodar, where the heating season lasts 149 days. Let's take the average heat loss for the heating season to be 5 kW. Let's calculate the amount of thermal energy required for this period:
5*24*149=17880 kW
In the first case, with a COP of 3.75, the heat pump will “eat up” 4768 kW (17880/3.75=4768).
In the second case, with a COP of 3.25, the heat pump will consume 5501 kW (17880/3.25=5501).
The difference will be: 5501-4768=733 kW. At a price per kilowatt of 4 rubles, we get 733*4=2932 rubles. Some will say that this is not much. Perhaps so, but heat pumps come in different capacities, heat losses differ and the amount can amount to more than tens of thousands of rubles. So this point must be taken into account.
Optional equipment
Selecting additional equipment for a heat pump is a responsible task, the solution of which largely determines the long-term service life of the heating system as a whole and the absence of operational problems.
Submersible pump for wells and reservoirs
If the system uses a heat pump to supply hot water, then a device with low power can reduce the pressure in the taps. A powerful pump will solve this problem, but it consumes more energy. The minimum permissible power when operating a GSV is 1 kW.
There are many different modifications of submersible pumps. The choice is made taking into account three criteria, these are:
- The amount of liquid used for pumping (the more water has to be transported, the higher the pump power must be).
- Well depth (the deeper the well, the greater the equipment power should be);
- Well diameter (traditionally, preference is given to 4-inch shafts, since the largest number of pumps have been created for them, as opposed to 3-inch ones).
To determine the depth of the well, it is necessary to attach a weight to a rope and lower it into the shaft. The wet part of the rope will indicate the full depth of the well, the dry part will determine the distance from the beginning of the water to the surface.
The pump is immersed in the wellbore to a depth specified by the device manufacturer. Usually the technical passport indicates how many meters there should be between the water surface and the pump, the bottom of the excavation and the pump
Both universal pumps and equipment specifically designed for wells can be suitable for mines. If the mine was developed by professionals, then it is less clogged with sand, so you can safely use a universal pump.
Pumps designed specifically for wells are more expensive, but they cope well with sand and dirt and become less clogged. Universal ones are sensitive to high organic content; they must be regularly cleaned of dirt, as a result of which their service life is reduced.
Preference should be given to pumps with automation, since if the motor overheats, there is excessive blockage or there is no water in the well, they turn off on their own, as a result of which the motor does not overheat and fail.
Based on the principle of operation, there are 2 types of submersible pumps:
- Centrifugal.
- Vibrating.
For work in wells producing water in limestone, centrifugal deep models are preferable. They are sensitive to water with grains of sand and clay suspension.
If the heat pump will be connected to an open reservoir, it is better to use surface pumping equipment designed for pumping dirty water, or an inexpensive vibration device.
Heat pump intermediate heat exchanger
In heat pumps, the freon may not be cooled well enough during circulation, causing the compressor to overheat due to excessive discharge temperatures. Therefore, it is important to improve the cooling of the substance, thereby reducing the pressure in the circuits.
There is another problem that is common to all heat pumps - the refrigerant can mix with water vapor. If liquid gets into the compressor, water hammer may occur. In this case, repair or replacement of the part will be necessary. Also, water can get into the oil, and it is difficult to remove it from there.
All the problems described above are solved by installing an intermediate heat exchanger. There are three types of heat exchangers - open type, shell-and-tube and coil.
The open type modification neutralizes the liquid that gets into the freon during circulation, which minimizes the likelihood of compressor water hammer. The device features high performance with minimal power consumption.
When installing an open-type heat exchanger, it is important to select the correct size of the liquid pipeline to ensure minimal pressure compression
Properly selected pipes will neutralize the possibility of boiling liquid. In this case, the valve must have sufficient throughput so that liquid can penetrate into the device at a low pressure difference.
The shell-and-tube heat exchanger is presented in the form of a closed structure. Heat exchange occurs through the walls of the pipes, and the liquid and refrigerant in it do not mix, unlike open ones, which provides high pressure for the circulation of steam and air.
The coil heat exchanger is distinguished by the presence of a flow regulator that controls the flow of liquid freon. The size of the device directly depends on the power of the heat pump. It is necessary to select a product taking into account the functionality and the amount available. It is advisable to give preference to collapsible models.
Heat pump filters
Water from wells or reservoirs does not come in pure form. It may contain sand, dirt, various trace elements - iron, hydrogen sulfide, manganese, chlorine, ammonia, etc. Before entering the heat pump, the water must be filtered.
First of all, it is necessary to eliminate large substances - stones, sand, dirt, silt. To remove them from the water, it is necessary to install a hydrocyclone.
A hydrocyclone is a device required for rough water purification. It must be selected taking into account the pump power
Next, it is important to install filters that eliminate iron, hydrogen sulfide, manganese, and ammonia. These microelements shorten the life of the equipment and expose it to corrosion.
You can use reverse osmosis filters, softeners, iron removers and their modifications. To provide drinking hot water, you should additionally equip it with carbon filters and a UV sterilizer that destroys bacteria and viruses.
Electric generator for backup power
Heat pumps operate from the electrical network, so if there is a power outage, the house will be left without heating. It is advisable to additionally purchase an electric generator that runs on flammable substances.
It is important that the electric generator can generate the necessary power to operate the pump compressor
Heat recovery circuits
When using the resources of reservoirs, open and closed type heat extraction circuits can be used:
- Closed-loop structures are installed on the bottom of the lake. In technical terms, such a circuit is a closed tubular loop with a liquid circulating inside, which transfers heat from the lake to the heat exchanger.
- When using an open version of the heat sink, water is taken directly from the reservoir. After the liquid passes through the heat exchanger, it is returned to the lake.
The main disadvantage of such systems is the mandatory frequent maintenance of the heat exchanger and the need to install additional elements that filter water.
If the source of heat is groundwater, then a system with wells or wells is used. The minimum number of wells is 2. The first well serves to supply water to the heat exchanger, which removes heat. A second well is needed to pump fluid back into the ground. When placing wells or wells, you need to ensure that the distance between them is more than 15 meters.
Features of operation of such a heat pump
Once a year, it is necessary to conduct an independent visual inspection of the pump components, follow the recommendations for maintenance - lubricate the parts in a timely manner, monitor the correct operation of the device when pumping water.
Some types of equipment require regular inspection (usually 1-2 times a year) by service center specialists. During the inspection, the following is revealed:
- engine oil leaks through cracks in the circuit;
- quality of fastenings and connections;
- pressure level in tanks and circuits;
- malfunctions in the power wiring.
The installation of a water-to-water heat pump should be carried out by trained specialists. The ineffectiveness of the system is most often due to its incorrect installation. Thermal equipment is suitable for use by both residents of the Southern and Northern regions.
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 ruined 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.
Part #1 - compressor
The easiest way to get a suitable compressor is to remove it from an air conditioner, for example, from an LG split system. The seven-watt compressor has a power of 9.7 kW for heat production and 7.5 kW for cooling. An additional advantage of such compressors is their 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, whose boiling point is -10 and condensing temperature is +55. In 2030, this refrigerant will be banned from use. A “younger” R422 freon may be a worthy alternative. However, you can change the refrigerant not only when creating a heat pump, but also at any suitable time.
Part #2 - capacitor
To make a condenser, you can use a stainless steel tank of approximately 120 liters. It is cut in half, a copper coil is mounted inside, connections with two-inch threads 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 = MT/0.8RT, where:
- PZ - coil area;
- MT — Heat power generated by the system, kW;
- 0.8 - thermal conductivity coefficient during the interaction of water and copper;
- RT is the difference in water temperature at the entrance to the system and at the exit from it, degrees Celsius.
To make a coil, a half-inch copper pipe, a special refrigeration pipe or clean plumbing pipe, is suitable. The recommended pipe wall thickness is 1-1.2 mm. To turn a piece of pipe of the required length into a coil, it is enough to wind it on any suitable cylinder, for example, on a gas cylinder. The ends of the coil are brought out using plumbing adapters. To ensure a tight connection, use flax and a clamping nut.
To make a coil for a water-to-water heat pump condenser, you need to carefully wrap the copper pipe around the cylinder. A metal strip will help fix the pitch of the turns.
Please note that the freon inlet should be located at the top of the condenser to prevent bubbles from forming.
Part #3 - evaporator
A plastic barrel with a volume of 127 liters is suitable for the role of an evaporator. It is more convenient if it has a wide neck. The evaporator is calculated in the same way as the condenser. A 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 neck. 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 homemade 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 draining water. When installing a thermostatic valve, before soldering the equalization line pipe, you should wrap it with a damp cloth, since this element cannot be heated to more than 100 degrees.
Assembly and refilling with freon
To assemble the prepared devices into a single system, you will need a welding machine. It is recommended to make a filling valve at the entrance to the compressor, which will be useful in the future. Then, using a special vacuum pump, you should check the system for vacuum.
To charge the system with freon, you will need a cylinder containing at least 2 kg of refrigerant. After refueling, it is recommended to wait several days while checking the pressure in the system. If it remains constant, then there are no leaks. If the pressure decreases, you can determine the location of leaks in the simplest way: using soap foam. For inexperienced technicians, it is better to contact a specialist who will refuel the equipment professionally and reliably.
To automatically regulate the operation of the system, 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 value is 40 degrees) and at the outlet of the evaporator (shutdown temperature is 0 degrees to prevent the system from freezing). If a controller is used to take into account the readings of both temperature sensors, you should remember that its settings may be lost if there is a power outage.
This is what one of the options for a homemade water-to-water heat pump looks like. The top of the device is covered with a metal casing 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 collecting and discharging groundwater and connecting the external circuit to the system. In areas where drilling wells is associated with certain problems, this issue should be addressed first. If wells cannot be drilled, you may have to choose another heat pump option, such as ground-to-water.
Conclusions and useful video on the topic
The video will introduce you to the principle of operation and features of the device:
As a result, we can conclude that a water-to-water heat pump is considered an effective environmentally friendly equipment designed to heat houses up to 150 square meters. Arranging a larger area may require quite complex engineering surveys.
If you have any questions while reading the information provided, please ask them in the block below. We are waiting for your comments, questions on the topic, stories and photos about the construction of a mini-hydroelectric power station with your own hands. We are interested in your opinion.
Recommendations for choosing a model
In order for the heat pump, the operation scheme of which is described above, to demonstrate high efficiency, you should know how to choose the right equipment. It is highly advisable that the selection of a water-to-water heat pump (as well as “air-to-water” and “earth-to-water”) is carried out with the participation of a qualified and experienced specialist.
When choosing a heat pump for water heating, the following parameters of such equipment are taken into account:
- productivity, which determines the area of the building the heating of which the pump can provide;
- the brand under which the equipment was manufactured (this parameter must be taken into account because serious companies, whose products have already been appreciated by many consumers, pay serious attention to both the reliability and functionality of the models they produce);
- the cost of both the selected equipment and its installation.
Equipping a boiler room with a heat pump
When choosing heat pumps water-to-water, air-to-water, earth-to-water, it is recommended to pay attention to the availability of additional options for such equipment. This includes, in particular, the following opportunities:
- control the operation of equipment in automatic mode (heat pumps operating in this mode due to a special controller allow you to create comfortable living conditions in the building they serve; changing operating parameters and other actions to control heat pumps that are equipped with a controller can be performed using a mobile device or remote control );
- using equipment for heating water in a hot water supply system (pay attention to this option because in some (especially old) models of heat pumps, the collector of which is installed in open reservoirs, it is not available).
Assembling a pump from an old refrigerator
There are two ways to make a heat pump from an old refrigerator.
In the first case, the refrigerator must be located indoors, and 2 air ducts must be laid outside and cut into the front door. Air enters the freezer through the upper one, the air is cooled, and through the lower air duct it leaves the refrigerator. The room is heated by a heat exchanger located on the rear wall.
Using the second method, making a heat pump with your own hands is also quite simple. To do this, you will need an old refrigerator; it just needs to be built outside the heated room.
Such a heater can operate at outside temperatures down to minus 5 ºС.
Flaws
- Price. The main disadvantage of water heat pump systems is their high cost. The price of equipment is quite high, starting from 150 thousand rubles. A number of additional costs may be required for drilling wells, purchasing related equipment and components. Don’t forget about the cost of installing the system and setting it up.
- Very coldy. In regions where in winter the air temperature drops below 20 degrees, additional devices for heating the room will be required. A water heat pump cannot provide heat to a large house. Of course, you can purchase expensive models with high power, but their maintenance costs will be higher.
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I hope my article today was useful and understandable to you. Write in the comments what you think about the water heat pump and whether you would like to install it in your home. If you already use a similar device, then I will be glad to read your impressions of its operation.
