Heat pumps are replacing heating boilers because they use an inexhaustible source of heat- the energy of the sun absorbed by the earth, water and air. They are compact, easy to tie, and require only periodic checking and inspection during operation. Requires only a few kilowatts of electricity
Modern HP models are equipped with economical, low-noise, reliable scroll compressors
One of the first domestic models of household TN-ATNU-15
23kW of free heat using ground probes with a depth of about 38m supplies the HRN unit from CLIMAVENETA
The heat exchangers of the evaporator and condenser in the first models of heat pumps were made of copper tubes by soldering
Robust model45 (THERMIA) uses the collected heat almost without loss with the help of a sub-cooler and develops a power of 45kW. FROMwith additional cooling units in summer it can replace a multi-split system
Many HP models are equipped with a flowing electric water heater
ТНСО2–20 runs on environmentally friendly CO refrigerant2Directly from a deep well into the house (through the floor with the help of a heat and waterproofing sleeve), at the stage of construction of the box, a head of a vertical collector was introduced that collects the dissipated heat of the soil
Pump inlet and outlet piping is carefully insulated to reduce heat loss
Wells (diameter up to 165mm) under the ground probe is placed near the house, taking into account the possibility of access to the drilling rig. They don’t reach artesian water
When planning the landscape of the site, we decided to cover the collector with a high embankment
Horizontal collectors are sometimes made in the form of a spiral with a diameter of about 1m, in increments of 0.3- 0.7m and laid in ditches up to a depth of2.5 m
Entrance of a vertical collector into a well without casing
IVT’s Greenline series models are built on a modular basis and are easily reconfigured to work with water or antifreeze.
Models of the Vitocal series (VIESSMANN) are available in three types:
“ground-water”, “water-water”, “air-water”; cover a range of capacities up to 106kW; controlled by weather-compensated controller C60
The WPC unit (STIEBEL ELTRON) “feeds” on the heat of the earth and works for three: in addition to the usual duties of heating the house and preparing hot water, it can switch to cooling water in fan coil units or radiators, thus operating as a multi-zone air conditioning system
Among the THERMIA units, the Diplomat series is designed to supply heat and cold in different ways- take heat from the earth and water or air (with the Aer block), and together with the passive cooling block- create coolness in the house
one- low-temperature heat supply circuit;
5- high-temperature heat supply circuit;
6- throttle valve
ATin a house with large heat losses, install a high-power pump (more than 30kW) is unprofitable. It is bulky, and will work at full capacity for only aboutmonth. After all, the number of really cold days does not exceed 10–15% of the duration of the heating season. Therefore, often the power of the HP is assigned equal to 70–80% of the calculated heating. It will cover all the heat needs of the house until the outside temperature drops below a certain calculated level (bivalence temperature), for example minus 5–10
Today we have opportunities to fully use the advantages of heat pumps. Andalthough hardly a third of the world’s HP manufacturers supply us with their products, their dealers are ready to install equipment anywhere in the country. Small business- for the desire of the European to bend down and take the heat from under their feet.
On the market you can find heat pumps from IVT, MECMASTER, THERMIA (all- Sweden), OCHSNER (Austria), VAILLANT, VIESSMANN, STIEBEL ELTRON (all- Germany), CLIMAVENETA (Italy), CARRIER, AERTEC (both- USA), PZP KOMPLET, G‑MAR (both- Czech). In addition, in the off-season, we have long used air conditioners and chillers with the “heating” mode from such well-known manufacturers of refrigeration equipment as HITACHI,
A wide range of HP models with power from 2 to 130kW is able to satisfy any requests of the inhabitants of both small cottages and large mansions. It is only necessary not to make a mistake with the choice of the type of installation.
Primingis perhaps the most versatile source of dissipated heat. It accumulates solar energy and is heated from the earth’s core all year round. At the same time, it is always “underfoot” and is able to give off heat regardless of the weather. After all, at a depth of 5–7m temperature is almost constant throughout the year. For central Europe, it is 5–8
There is another scheme for collecting heat, when instead of “brine” freon circulates in the circuit, which turns into steam right in the pipes of the heat collector. This is how, for example, the pump ATNU-10 (RZP) or Golf-GMDW (OCHSNER) can work. But although this scheme improves efficiency, its operation is difficult. Today the most popular systems with “pickle”. ATThey use two types of heat exchangers: ground collector and ground probe. Both are made of polyethylene pipes with a diameter of 25, 32 or 40mm (the more- the better the heat extraction, but the more expensive the system).
Ground collector (horizontal) is a long pipe laid horizontally under a layer of soil. Main advantage- versatility and ease of installation. Found a free space- dig grooves and stack. Flaw- large required area under the collector- 25–50m2 per 1 kW of power (moreover, the site can only be used for a lawn or annual flowers). There are different pipe layout schemes: loop, snake, zigzag, flat and helical spirals of various shapes andt.n. The choice is determined by the thermal conductivity of the soil and the geometry of the site. The heat collection capacity is higher in moist loams and lower in dry sandy areas. ATaverage 1m2 ground surface can provide “supply” 10–35W of power. The length of the pipe in one loop, and one-piece, without connectors, tends to be limited (no more than 600m), otherwise the energy consumption of the circulation pump increases markedly. If more power is needed, several loops are made.
Atcollectors have a feature that gives a lot of trouble to builders. It turns out that the temperature of the soil layer around the pipes gradually decreases, and the stronger, the higher the performance of the HP. It can fall below zero, and the array can even freeze. Therefore, the main concern of heat collector builders- to make it for a reasonable price so that the soil has time to gain “thermal fat” over the summer and at the same time continues to supply energy for the preparation of hot water. There are no uniform norms here, because soils and climatic conditions are zoned. So, in the world region, the TN-SERVICE company has been successfully practicing pipe laying just below the freezing depth (1.5m) with a step calculated from the condition of 2 running meters. m pipe per 1m2 heated area of the house. BUThere, near , specialists from the company “TEPLOSERVICE” deepen pipes by only 1.2m, which is higher than the freezing depth, and in increments of 1m. In the spring, when heat reserves run out, the upper layer of the earth warms up faster with the energy of the sun and melt water. Izhevsk company “ECOSERVICE” uses a step of 0.6m and depth 1.5On the contrary, specialists from the Belgorod organization “GROUND CONSTRUCTION” abandoned ground collectors because of their lower efficiency compared to ground probes or pumps “air- water.
Ground probes (vertical collectors)is a system of long pipes lowered into a deep well (50–150m). Here you need only a patch of land, but expensive drilling work is required (from $20 for 1 line m). The temperature is always the same at depth- about 10
A dozen different designs of probes are known, sometimes very unusual (for example, in the form of pipes immured in the piles of the foundation of a house). But the most applicable are two: pipe in pipe and U‑shaped. On one line, the “brine” is fed down by the circulation pump, on the other it rises up to the evaporator. ATin deep wells, the assembly is always protected by a casing pipe, in shallow wells it is not always.
To improve heat transfer and increase the strength of the probe, the gap between the ground or casing and working pipes is filled with bentonite or concrete. If you need to get more power, there are several such heat collectors. Distances between them- 5–7m.
Atvertical collectors, in addition to high cost, there is another weak point, which is not mentioned in company brochures. As shown by studies conducted by one of the pioneers of the introduction of HP- by INSOLAR-INVEST, the balance between the processes of heat extraction and restoration of the “feeding” capacity of the soil (the earth around the probe becomes cold) occurs only after 4–5 years of operation. Therefore, the pump in the project must be laid more powerfully. How much- only experts can say.
BUTwhat can really cause a lot of trouble is getting permission from the water supervision service to drill a deep well for a probe. For the probable freezing of the soil can disrupt the behavior of aquifers. Therefore, for small cottages, specialists from INSOLAR-INVEST advise laying several smaller ones instead of one deep one (25–35m) wells, since they do not require the approval of an official. Idea tested. FROMWith the help of eight shortened probes and the heat of the exhaust air, a plant for supplying hot water to a seventeen-story building in the world was assembled, the residents of which are 45% cheaper than those in neighboring houses.
Scheme of installation of TN type “soil-water”:
3- heating system;
four- DHW network
The source of heat can be surface water (rivers, lakes) or soil water (wells), as well as waste water from technological installations. The pumps themselves are almost the same as those that work with the “brine”. But due to the higher temperature of the coolant in winter, the annual efficiency of using water-to-water devices is the highest. It is a pity that this technique is good mainly only for industrial applications. Too rarely there are suitable conditions for a private trader. But if a non-freezing river flows nearby, you can lay a loop of pipe with antifreeze on the bottom (by drowning it with loads) and heat up almost for nothing. Of course, if the water protection service gives the go-ahead.
The well is more difficult. Water from it (at the rate of about 0.25m3/h per 1kW of thermal power) is supplied by a borehole pump directly to the evaporator, and drained … into a second well, remote from the first downstream water in the underground layer by 15–20m. In this case, the aquifer must accept and divert the drained water, otherwise a small flood is provided to you. It is clear that such formations at shallow depths are not found everywhere, and for artesian wells it is not easy to get permission from us. AndIt is also necessary to protect the evaporator from contamination and corrosion. Filtration and water analysis are required. If there are too many salts in it, it will be necessary to equip an intermediate heat exchanger, deaerated clean water will circulate between it and the HP.
In terms of versatility of application in European conditions, this type of pumps is still in second place. Andthe pumps themselves are cheaper, and pipes (with the same earthworks) are not required. There is only one drawback, but a significant one: you can’t take much heat from the frosty air. Steadily, albeit with reduced power, these devices operate down to ‑15
When it comes to the choice of “air” units, it is useful to take into account two important circumstances that are usually silent in articles. Firstly, the value of the rated power given in the passport refers to a certain temperature of the outdoor air. Ateach company has its own. It can be 0 or 2 or 10 or even 25
Scheme of application of HP “air-to-water” and solar water heater:
2- heater panels;
3- heat accumulator;
Structurally, air-to-water devices are made according to two layout schemes: split and mono. ATIn the first case, the installation consists of two blocks connected by communications. One, outdoor, includes a powerful fan and evaporator (mounted on a site near the house). The second, internal, contains a capacitor and automation and is installed indoors. The compressor can be located either outside, so as not to make noise in the house, as, for example, in the HP-40 (G‑MAR) model, or in the indoor unit, as in TCLM (PZP). ATmonoblocks, all elements are assembled in a common housing and mounted in the house, and connected to the street by a flexible duct. They are supplied by most companies, but have limited capacity.- usually 3–16kW. There are monoblocks that allow both external and internal installation, for example WPL (STIEBEL ELTRON). Newly developed, monobloc for outdoor installation with a record low operating temperature (-25
ATIn recent years, due to the deterioration of housing ventilation due to the widespread use of new sealed windows with double-glazed windows, air-to-water heat pumps have received additional development. In addition to heating and hot water preparation, some models “learned” not only to work in ventilation systems, but also to use the heat of the exhaust (exhaust) air of the premises. These are, for example, Europa and Combi from OCHSNER, IVT490 and 495 from IVT, ComfortZone from MECMASTER, Solvik from THERMIA.
Ocoordination of the operation of the pump with connected circuits (for example, heating) and we will talk about the features of these circuits in a separate article.
Characteristics of heat pumps for houses up to 200m2
|Manufacturer (number of household models)
|Thermal power, kW
|Power consumption, kW
|Europa 122 LHK
|STIEBEL ELTRON (28)
|Greenline E11 Plus
|G‑V, V‑V, Voz‑V
|PZP KOMPLET (23)
|“NPF TRITON” (2)
|Note. G‑V- “soil-water”; B‑B- “water-water”; Woz‑B- “air-water”
The editors thank the firms TN-SERVICE, INSOLAR-INVEST, TEPLOSERVICE, TERMOTECH RUS, ELEVATOR-SPETSSTROY, GROUND CONSTRUCTION, ECOSERVICE, EKIP, TERMOSFERA and representative offices of VIESSMANN, STIEBEL ELTRON for help in preparing the material.