To supply large amounts of heat, HPs are easily connected in cascade
The heat pump (left) fits well into the interior of the kitchen
a bivalent system was used in the piping of the boiler room- HP together with an electric wall-mounted boiler
ATdesign of the Robust brand heat pump uses a scroll compressor (THERMIA)
Options for laying out soil collectors: in a swamp; in solid ground (“TEPLO-SERVICE”)
Sometimes a sand embankment is made over shallow trenches.
It is permissible to drill a well for a probe even at the border of the site
Assembly of heat-removing loops with distributor
collectors. A concrete manhole will be erected around them later.
Laying the branches of the underwater collector manually
Distribution manifolds for underwater heat removal loops
Toa heavy anchor sleeve is suspended from a probe filled with water and carefully lowered into a freshly drilled well
Wells for probes are drilled at a distance of no closer than 2m from the walls of the house, so as not to damage the foundation
Distribution collector placement options
ditch: in the pit in front of the building and in the house
The steel piping at the head of the vertical tube-in-pipe probe is not durable, but can be easily replaced with new ones.
The place where the pipes of the thermal circuit enter the boiler room through the floor will be foamed, covered with expanded clay for insulation and cemented after the system is debugged
The piping of the heating circuit is often made of copper pipes.
Heating system manifolds
ATexpansion tanks are required on both circuits
A design option for the input unit to the boiler room from the field distributor
The secondary circuits of two HPs were connected to the heating mains in parallel using polypropylene
When using heat pumps, it is necessary to use steel panel radiators with an increased area due to the low water temperature
Since childhood, we secretly believe that some miracle will happen on the New Year, even a small one. BUTafter all, there is already a miracle in the world that brings great benefits to people, but we stubbornly do not notice it. We are talking about heat pumps. They are able to collect crumbs of heat from the frozen ground, from under the ice or from the frosty air and create a comfortable microclimate in the house due to this.
Winter cold outside the window involuntarily makes you think about reliable heating. For the inhabitants of millions of country houses, where heat pipes from district boiler houses have not reached, this is an acute problem. After all, you can’t complain about DEZ and you can’t blame the authorities for inaction. Meanwhile, you can uninterruptedly receive cheap heat and hot water all year round. Andall thanks to heat pumps (HP). They have been known for 150years, and in private homes only 30years.
Arrangement of a boiler room using a heat pump and a heat point cabinet (“KORSA”) containing all the fittings, wiring and circulation pumps of the primary and secondary circuits. These devices are popular all over the globe, except for Europe. Moreover, the population of developed countries uses them not only for heating houses and obtaining hot water. They (although not all models) are also able to create a cool atmosphere in the room and work in a forced ventilation system, heating cold fresh air or dehumidifying room air. Andwhat makes this not a huge rumbling technical monster, but a modest device resembling a refrigerator. It can stand in the corner of your kitchen (appearance allows) or take 2–3m2 in a small boiler room. But most importantly- in a different. Approximately 70% of the energy to create a comfortable climate in the house TN simply gives its owners. Is free! Because he takes it from the surrounding nature- from air, land or water. Isn’t it a miracle? Don’t be lazy, use it! About how “it” works, we wrote in N6 “IVD” for 2005G.
Note that the device itself does not generate energy, but only transports it from a low-temperature heat source (LTH) to a higher temperature level.
“Don’t miss, Asunta!”
The TN market is very modest. Models for water heating offer IVT, MECMASTER, THERMIA, NIBE (Sweden), VIESSMANN, STIEBEL ELTRON (Germany), OCHSNER (Austria), CARRIER, AERTEC, FHP (USA), CLIMAVENETA (Italy), PZP KOMPLET, G‑MAR ( Czech Republic), GEOTHERMIX (Canada). For air heating model type “soil- air” is supplied only by FHP. It is gratifying that among domestic manufacturers (EKIP, NPF TRITON, RZP, NPO ENERGIA) a newcomer- the company “KORSA”. It offers eight models of “ground- water “with a capacity of 11–34.5kW at a price of approximately 9.2thousandrub. for 1kW.
The peculiarity of the HP market lies in the fact that you cannot point your finger at the unit you like, such as, for example, at a kettle. Models are presented only in catalogs, but they are not in stock. Your choice will only start the discussion. The firm’s specialist will carefully examine the house (or project) to determine the heat loss of the building, and the site to assess its thermodynamic potential. According to the recommendations of a professional, the model you have chosen can be significantly changed by adjusting its parameters to the needs of the house (like a suit according to the figure). TN will be created at the plant, in fact, to order. Andyou will receive it throughmonth.
A boiler room with a heat pump is easy to tie. The heat pump is adjacent to the workbench (“TERMOTEH‑M”) But the primary choice is extremely important (it’s like a sighting shot from a sniper). The success of the business depends on how competently the parameters of the HP itself, the low-grade heat collection system (primary circuit) and the house heating system (secondary circuit) are coordinated.
Firstly, HP is recommended to be used for low-temperature heating systems (Europe switched to them when using any type of energy). The most profitable options- floor water or air heating, in which the coolant is above 35
In addition, it is recommended to use HP in the so-called bivalent heating systems and hot water supply (DHW). The term means that in addition to the HP, a second heat supplier works in the system. There are two reasons for its use: physical and economic. The consumer often needs hotter water than the pump can “offer”. Typical situation: you need water with a temperature of 75–85
The “assistant” is especially useful when starting the HP for the first time in a cold house. Most often, an electric heating device (heater or electric boiler) is used as the “second”. In many models, heating elements (with a capacity of 3–12kW) are already built into the design. Water, preheated by a pump, they easily bring to the desired temperature. The problem is different: where to find these additional kilowatts of electricity. If a monovalent system is used, then only the HP (or the HP cascade) provides all the needs. But water in the DHW system will have to be supplied at temperatures up to 45
Most often, the bivalent system is used for economic reasons. The share of the second heat source in annual energy costs is 10–15%, and in general the project becomes cheaper. “Assistant” is chosen based on the most affordable type of fuel. It can be a small gas, diesel, electric or even wood-burning boiler.
Nevertheless, for operation in monovalent mode, the market offers a line of HPs with a capacity of up to 100kW.
If it is impossible to get the required electrical power from the municipal network, you can mount a solar photo panel on the roof. Together with HP, it will provide year-round heating at home. It makes sense to talk in more detail about the cost-effectiveness of using HP. It is not as stunning as it seems when reading advertising booklets. Indeed, about 70HP offers % of heat for free, although not without a “but”. First, the suppliers of the equipment collect their rent from the obvious benefit of the offer. BUTtheir appetites are clearly not regulated by the laws of cost (compare the design complexity of a car engine and a pump at the same price). Secondly, the cost of arranging the primary heat collection circuit is 70–150% of the equipment cost. Thirdly, local prices for electricity and alternative heat sources are strongly affected. Savings from HP arise due to reduced energy costs, depreciation (equipment service life- thirtyyears, primary circuit- fiftyyears) and maintenance. ATon average, capital investments in HP reach 20–40.5thousandrub. for 1kW of power and in relation to diesel boilers pay off in 3–7years. According to MZTA specialists, the use of HP is no less profitable than gas heating. Calculations showed that the pump after 18–20years is even beginning to bring benefits. No other competing equipment can do this.- it just physically fails for such a period.
Parameters of ground collectors from PE pipes, m
Our most common source of low-temperature heat is the soil. Heat is taken from it by soil heat collectors of two types: a) horizontal soil collectors; b) vertical geothermal probes. ATThey contain a non-freezing coolant, which, heating up from the ground, transfers heat to the HP evaporator using a circulation pump. Studies conducted by INSOLAR-INVEST have shown that sufficiently efficient heat removal can be carried out almost throughout Europe. What type of heat collector is preferable for a particular area, the specialist decides.
Experience shows that the most acceptable design of the heat collection system is obtained by using polyethylene pipes PE PND6 with a diameter of 32mm filled with propylene glycol (30%). So, for a house with an area of 100m2 we recommend a pipe with a total length of 300–400m. Enough two segments of 200m. For laying each branch, they dig a trench up to 50 longm, width 0.8m and depth 2m. A clay base is poured onto its bottom (5cm). Then, near the trench wall, a pipe filled with water under pressure is laid in the forward and reverse directions 4atm. From above it is covered with a layer of clay with a thickness of 10cm, which is rammed and spilled with water. Then lay the soil with a thickness of 20–30see, and on top, in a clay “pie”,- the rest of the pipe. Its ends lead into the room in such a way that there is not a single extension joint outside. The second branch is laid in the same way. In this case, the distance between the trenches is at least 10m. Vthe circuit is embedded with a circulation pump, which is coordinated with the parameters of the circuit and HP (the “circulators” are deliberately not included in the design of our HP).
Ilya Moskalenko, General Director of KORSA
Ground collectors. They collect the heat accumulated in the upper layers of the soil (depth- 5–20m) as a result of solar radiation (direct heating, precipitation, air heat). Radiation radiation of the Earth, coming from the depths, does not exceed 0.12W/m2 and does not make the weather.
A soil flat collector consisting of six loops is laid on the field. Each of them has a manhole at the point of connection to the distribution
collector The heat removal depends on the composition and structure of the soil. The best results are achieved if it contains a lot of water, hard mineral constituents such as quartz and few air pores. The heat removal power is 10–40W/m2 (with a pipe spacing of 0.5–0.7m). The removal of heat is accompanied by a cooling of the area around the collector pipes until they freeze. Freezing temperatures outside exacerbate this danger. With intensive heat removal, it is not possible to achieve a balance of heat removed from the collector to the pump and received from adjacent land masses due to the low thermal conductivity of the soil. Stable withdrawal process- supply” of heat occurs, according to “INSOLAR-INVEST”, only in the fifth year of operation of the equipment. In this case, the heat output of the pump is reduced. There are installations in which HP sends excess heat from the house back to the collector and further into the ground for storage in summer, but we are almost never used.
For the efficient operation of the system, experts, based on the characteristics of the soil at the site, offer a variety of collector designs. Of the two main groups- flat and spiral- the first ones are getting accustomed to us. Pipes are laid in trenches, placing them on a plane in the form of a snake, loop, spiral. After checking the tightness of the system, the trenches are covered with earth. The depth of the pipes, their spacing and layout are the know-how of the firms. The area of the plot required for laying the heat collector is 2–3 times greater than the heated area of the house. Use this area only for a lawn or flower garden.
When the collector is located at a great distance from the house, they are interconnected by pipes with a diameter of up to 140mm to reduce hydraulic resistance. Heat collectors are made of PE HDPE pipes with a diameter of 25–40mm, designed for pressure 6–10bar. Zinc plating is not allowed. The total length of the pipe is divided into segments of 100–200m. They are laid in separate loops (circuits) and connected to two distribution manifolds- serving and returning. The contours are made only from a whole piece of pipe, without joints lying under a layer of earth. It is important that they have the same hydraulic resistance, otherwise the less “clamped” one may freeze. After all, more antifreeze will flow through it and heat removal will become more intense.
Distributors can be located both near the house (in a concrete pit) and in the building itself. Access to connections and thermal insulation of pipes should be provided at the point of entry into the house and at a length of at least 3m in front of the house. ATas a coolant in the circuits, a 30% solution of propylene glycol or ethylene glycol is used, less often- alcohol solutions.
Practice shows that even in the northern latitudes, heat pumps are able not only to provide a comfortable microclimate in the house, but also to keep the average annual temperature potential of the soil at the same level. Good results are obtained by schemes using an IVT-compact collector in the primary circuit and a Greenline heat pump (IVT) paired with a VBX-IVT unit. The IVT-collector is assembled from modules in the form of a lattice of PE M40 pipes (module width- 1.5m, height- 2m). The collector branch is often located in a trench with a width of 0.5m and depth 3m vertically and connected to the house in the usual way. The building is equipped with a forced ventilation system. The VBX recuperation unit built into it is connected to the HP evaporator, transferring the heat of the exhaust air to it, and to the condenser, heating the fresh air. In warm weather, excess heat is taken away by the collector coolant and the soil. ATas a result: a) the ground around the collector does not freeze and the performance of the HP increases; b) a favorable microclimate is created in the house; c) it becomes possible to shorten the heat collection circuit (since part of the heat is supplied by air), which makes it possible to reduce the cost of earthworks.
Oleg Prokhorov, technical director of the company “TEPLOSERVICE”
geothermal probes. They extract heat from greater depths, where the ground temperature is more stable (about 10
The base of the U‑shaped geothermal probe with an eye for hanging the “anchor” (“EC “SOLAR TECHNOLOGY”) The main advantage of the probes- small installation area. Flaw- high cost of drilling (up to 1thousandrub. for 1linearm).
Two types of vertical collector designs are common: pipe-in-pipe and U‑tube. ATthe first case is a plastic pipe (diameter 32–50mm) runs along the axis of the steel pipe (diameter 100–120mm), which is welded at the bottom and provided with a connecting flange at the top. This design successfully resists ground movement and provides good heat transfer, but is difficult to assemble. After all, sections of a steel pipe have to be welded not only very reliably (God forbid antifreeze leaks!), But also quickly so that the walls of the well do not have time to crumble.
The tubes of the probe are connected to the metal base, filled with water and pressed under a pressure of 6 atm to check the tightness. In the second design, plastic pipes (PE) with a diameter of 25- 40mm are hermetically connected at the bottom, forming a long U‑shaped channel filled with antifreeze. Such loops are most often used in pairs, but there may be more of them in the probe. The pipes are pressed with liquid and lowered into the well when filled. After that, the space around the probe is filled with drilling fluid or concrete-cement mixture (to protect pipes from mechanical damage and better heat transfer). If the well will pass through aquifers, permission from the authorities must be obtained to carry out the work. These troubles can be avoided if the well depth is reduced to 20–40m, and their number- increase, placing no closer than 5m from each other. At the top, pipes are led through a trench to the house.
All heat collectors are equipped with an expansion tank, an air vent and valves for filling with antifreeze. The main condition for the coordinated operation of the INT circuit with a heat pump- ensuring such a flow rate of the coolant, which is indicated in the passport of the HP.
sun, air and water
A lot of solar energy is stored in air and water. HP, taking heat from the air, are quite effective in the southern regions. ATtheir use is limited in the middle lane. The fact is that in winter they can only work as part of bivalent systems and at temperatures not lower than 0 … ‑5
Scheme for converting energy into HP:
a- heat circuit INT; b- energy of freon vapors; in- electrical energy for the compressor; G- thermal energy at the HP output; one- evaporator; 2- compressor; 3- capacitor; four- throttle.
Scheme of air HP operation in cooling mode:
a- evaporator; b- throttling valve; in- reverse valve; G- capacitor; d- compressor; e- water from INT.
The editors would like to thank TEPLOSERVICE, TERMOTECH‑M, INSOLAR-INVEST, KORSA, SOLAR TECHNOLOGY EC, GEOTECH‑K, TN-SERVICE for their help in preparing the material.