Operating modes and capacity of the thermal pump

The choice of an operating mode and rated power of the thermal pump depends both on a source of low-potential energy, and from type of heating system in a building. Important at the initial stage to define all factors for selection of the most suitable operating mode and capacity of the thermal pump.

Operating mode of the thermal pump

There are two main working hours of heatpump system of heating:

  • The monovalency
  • The bivalent

Monovalency operating mode of the thermal pump

In a monovalency mode the thermal pump is capable to provide completely all thermal loading in a building. Thus the capacity of the thermal pump should be not less than peak capacity of system of a heat supply. As it is necessary that the maximum temperature of giving of the thermal pump would be higher, than the maximum settlement temperature in system of heating and hot water supply.

Operating modes and capacity of the thermal pump

Temperature schedule of a monovalency mode of the thermal pump

This operating mode most is suitable for thermal pumps with stable temperature of a low-potential source of heat (soil, ground waters, industrial utilization is warm etc.) in a combination to low-temperature system of heating (heat-insulated floors, фанкойлы etc.).

In spite of the fact that the thermal pump in a monovalency mode completely solves a heat supply question in a building, an essential lack of this mode is high initial capital investments on the equipment.

Bivalent operating mode of the thermal pump

For increase of profitability of the thermal pump it is necessary to choose a bivalent operating mode. The bivalent mode means operation of the thermal pump in a combination to other heating device: gas, electric, solid propellant copper, etc. The choice of this mode can be caused as by need of giving of more high temperature in heating system at low external air temperatures.

The peak capacity of system of heating pays off proceeding from the coldest five-day week in a heating season. In practice such low temperatures meet not often and not long. Throughout the most part of a season the heating system works at level less than 50 % from the maximum capacity.

Operating modes and capacity of the thermal pump

Temperature in a heating season

In the table the average number of hours with various temperature ranges for the heating period for Kiev is shown. Average temperature for a heating season +1,1? S.Kolichestvo chasov with temperature less than-10? With makes no more than 7 %. Therefore, having picked up peak capacity of the thermal pump, for example on temperature-10? With, it is possible to cut down initial expenses on the thermal pump, the additional equipment and installation works for 30-40 % thus to provide to 93 % of needs for a heat supply.

Operating modes and capacity of the thermal pump

Capacity of the thermal pump

In this example temperature-10? With to be called as temperature (point) of a bivalentost. At temperatures below a bivalentnost point the thermal pump can be disconnected or work together with an additional source of heat, but thus not cover all need for heat. In this regard, there are three types of a bivalent operating mode of the thermal pump:

  • The bivalent alternative
  • The bivalent auxiliary
  • The bivalent combined

The thermal pump in an alternative mode is provided full thermal by building loading yet will not reach a bivalentnost point. After that it is disconnected, and all loading is assumed by the auxiliary heatgenerator which provides the necessary temperature schedule.

Operating modes and capacity of the thermal pump

Bivalent alternative operating mode of the thermal pump

The additional source of heat pays off on the maximum thermal loading. More often such mode meets, when as an auxiliary heater the solid propellant copper or a fireplace with a water shirt acts.

At an auxiliary operating mode the thermal pump as completely provides thermal loading to a bivalentnost point, however at achievement of a point it is not switched off, and works together with an additional teplogenenrator.

Operating modes and capacity of the thermal pump

Bivalent auxiliary operating mode of the thermal pump

Function of the auxiliary heatgenerator consists in providing the corresponding temperature mode after bivalentnost temperature. In that case the capacity of an additional source of heating can get out proceeding from missing capacity of peak loading. More often it can be a small electroheater.

The combined mode combines in itself characteristics of the previous operating modes of the thermal pump. At achievement of a point of a bivalentnost the thermal pump is not disconnected, and works in parallel with the auxiliary heatgenerator to the minimum possible air temperature.

Operating modes and capacity of the thermal pump

Bivalent combined operating mode of the thermal pump

Such mode, as a rule, corresponds to operation of the thermal pump air-water. At low negative temperatures productivity of the thermal pump considerably falls, and expediency of its work sharply decreases or at all the compressor is not capable to give out heat. In that case in graphics the point of shutdown of the thermal pump is added. The capacity of the auxiliary heatgenerator should be, as in an alternative mode, is calculated on peak thermal loading.

Optimum capacity of the thermal pump

Optimum it is considered selection of capacity of the thermal pump of equal 60-70 % from rated power of a heat supply of a building. Thus the thermal pump as the main source of a heat supply, working in a bivalent mode can provide to 90-95 % of necessary heat. In practice the most widespread are an auxiliary and combined bivalent operating mode of the thermal pump. The point of a bivalentnost can be heating system different depending on type and type of the thermal pump.

Updated: August 24, 2015 — 12:42 pm