[ad_1]
-
Why is a heat pump needed? When should you choose a heat pump? Advantages
-
How a heat pump works
-
Energy source. Requirements
-
well
-
earth contour
-
water
-
warm air
-
-
Peak electrical heating. Why do you need
-
Air conditioning, passive and active. Principle
-
Heating system — heat pump and underfloor heating
Why is a heat pump needed? When should you choose a heat pump? Advantages
A heat pump is a modern source of energy used for the operation of air conditioning systems, heating, hot water supply. Unlike other heat generators (gas, diesel, electric), the heat pump «pumps out» the energy accumulated during the warm season from the environment — soil, rock, water.
What are the benefits of using a heat pump? First of all, it is an increase in the level of comfort. By choosing a heat pump over an oil-fired system, you will reduce your home’s fire hazard, get rid of the chimney, diesel smell, and the need to remember to order delivery on time.
If you would like to install a system that runs on electricity, but there is not enough connected electrical power at home for this, a heat pump can solve this problem — a quarter of the power needed for a traditional heating system is enough to use it. As an example, you can see a Swedish-made Thermia heat pump on the distributor’s website.
Thus, the use of a heat pump also saves energy and money. In Russia today, the cost of heat production depends significantly on the type of fuel: electricity is the most expensive, followed by diesel fuel and gas. But energy prices are constantly changing, and the difference between them is shrinking. At the same time, the difference in the cost of installing a heat pump with a ground heat exchanger and a diesel-fueled boiler house with a fuel economy, a chimney, an automatic control system will pay off in 3-5 years.
Popular Models
Heat pumps electric: all models
How a heat pump works
The source of heat can be rock, earth, water, air.
The coolant heats up by several degrees, passing through an external circuit laid in the ground or a reservoir. Inside the heat pump, the heating medium passes through a heat exchanger (evaporator) and releases the collected heat to the internal circuit of the heat pump. The internal circuit of the heat pump is filled with a refrigerant having a low boiling point, which, passing through the evaporator, turns from a liquid state into a gaseous state at a temperature of -5°C and low pressure. From the evaporator, the gaseous refrigerant enters the compressor, where it is compressed to high pressure and high temperature. Then the hot gas enters the second heat exchanger — the condenser, where heat exchange takes place between the hot gas and the heat carrier from the return pipe of the house heating system. The refrigerant, giving off heat to the heating system, cools and turns into a liquid, and the heat carrier of the heating system enters the heating devices. After passing through the condenser, the liquid refrigerant can be further cooled and the heating system direct water temperature increased by means of an optional subcooler. The refrigerant pressure, however, is still high. When the refrigerant passes through the pressure reducing valve, the pressure decreases, the refrigerant enters the evaporator, and the cycle repeats again.
Necessary requirements for the energy source
The source of energy can be soil, rock, lake, in general, any source of heat with a temperature of 1 degree Celsius and above, available in winter. It can be a river, the sea, the exit of warm air from a ventilation system or any industrial equipment.
The external circuit, which collects the heat of the environment, is a polyethylene pipeline laid in the ground or in water. The heat carrier is a 30% solution of ethylene glycol (or ethyl alcohol).
Well
When using rock as a heat source, the pipeline is lowered into the well. It is possible to drill several shallow wells — this may be cheaper than one deep one. The main thing is to get the total estimated depth.
For preliminary calculations, the following ratio is used — 50-60 W of thermal energy per 1 meter of the well. That is, to install a heat pump with a capacity of 10 kW, a well with a depth of 170 meters is required.
earth contour
When laying the contour in the ground, it is desirable to use a site with moist soil, best of all with close groundwater. The use of dry soil is also possible, but this leads to an increase in the length of the contour. The pipeline should be buried to a depth of approximately 1 m, the distance between adjacent pipelines should be approximately 0.8-1.0 m.
The specific thermal power of the pipeline laid in the ground is 20-30 W/m. Those. to install a heat pump with a capacity of 10 kW, 350-450 m of the thermal circuit is enough, for which a plot of 20 x 20 sq. m.
Special soil preparation is not required; the pipeline does not have an effect on plants if calculated correctly.
Water
The nearest body of water is an ideal source of heat for a heat pump. When using lake or river water as a source of heat, the circuit is laid on the bottom. This option is ideal from every point of view — «high» ambient temperature (water temperature in the reservoir is always positive in winter), short external circuit, high energy conversion efficiency of the heat pump.
There is approximately 30 W of thermal power per 1 meter of pipeline. Thus, to install a heat pump with a capacity of 10 kW, it is necessary to lay a 300-meter long circuit in the lake.
In order for the pipeline not to float, it is necessary to install about 5 kg of cargo per 1 linear meter of the pipeline.
Warm air
There is also a special model of a heat pump with an air heat exchanger for obtaining thermal energy from the air, for example, from the exhaust of a ventilation system. It can be used in manufacturing plants that produce large amounts of warm air (bakery, ceramics, etc.).
Such a model is also useful for a country house — for the operation of the hot water supply system in the summer.
Why do you need peak electric heating
Electric heaters are installed in almost all models of heat pumps. This is due to the fact that when choosing heating equipment, the calculation of the rated power when choosing heating equipment is done taking into account the coverage of the heat load on the coldest days, for example, for St. Petersburg, the minimum design temperature is -26 ° C.
But this temperature lasts only a few days a year, which means that the potential of the heat pump will practically not be used. It is economically more profitable to purchase a heat pump of less power, and on the coldest days to use electric heating.
The combination of two heat sources — generating cheap energy, but expensive (heat pump), and cheap, but generating expensive energy (electric heater) can reduce the cost of capital expenditures and increase the payback period of the heat pump installation.
To select the power ratio of the heat pump / electric heater, a special integrated graph is used, which is universal for all regions of Russia.
The principle of conditioning (active and passive)
In winter, the heat pump transfers heat from the environment, which is then used in the heating system. In summer, on the contrary, the «cold» from the well (7-9°C) is transferred to the premises of the house. The principle of operation of the system is approximately the same, only fan coil units are used instead of radiators. With passive cooling, the coolant simply circulates between the fan coil units and the well, i.e. cold from the well directly enters the air conditioning system — the compressor does not work). If passive cooling is not sufficient, the heat pump compressor is switched on, which additionally cools the heating medium.
Water heated floor and heat pump
The heat pump and the underfloor heating system seem to be specially designed for each other. The technical features of the heat pump are such that the temperature supplied to the heating system is usually not higher than 55°C, and the return water temperature should not be higher than 50°C. When using traditional radiators, careful calculation of heating devices is necessary. For a warm floor, this temperature is quite enough.
By installing a heat pump in an underfloor heating system, energy will not only be economically produced, but also economically distributed. A heat pump saves up to 80% of energy compared to using traditional heat sources, and a warm floor saves 10-15% of energy compared to radiator heating systems.
Popular Models
Gas heat pumps: all models
Source: TopClimat.ru
[ad_2]