4.9.2008
How is the heat pump functioning?
In its principle, the heat pump works as a cooling device the driving unit of which is a spiral compressor. In its evaporator, the device takes out heat from the environment; this environment is thus cooled down and by means of driving electric power in the condenser the heat is transferred into a medium with a higher temperature, e.g. heating water, to warm it up.
In transfer from the evaporator into the condenser the heat increases by heat developed from driving electric power conversion in the compressor. As against other sources, the exclusive advantage is a positive ratio of the supplied and produced energy. From 1 kWh of electric power the heat pump can produce 3 to 4 kWh of heat.
What is the meaning of terms „air – water“, „earth – water“, „water – water“ ?
These terms denote the systems of heat pumps. The first word denotes the substance or environment from which low-potential heat is gained, e.g. external air, earth – soil, underground (well) or process water. The second word denotes the substance or medium into which heat is transferred. This is mostly heating system water in the case of heating, in ventilation units with heat pumps it is ventilation air.
What is it the heating factor?
The heating factor is a ratio of heating performance and heat pump electric demand. Its value is depending on the conditions in which the heat pump operates and is always higher than 1. The higher is this number, the more effective is the heat pump.
What is heat pump noise level like?
The heat pump noise level is comparable with that of a bigger freezer. The values for noise levels can be obtained from the heat pump manufacturer or a certified design company. Solid manufactures enable to their potential customers to listen to reference heat pumps when in operation.
Is an ecological cooling agent in the heat pump?
Yes. The PZP heat pumps always work with ecologically suitable cooling agents R 404A, R 407C, R 134a containing no chlorine and non-impairing the ozone layer. Until recently some heat pumps of other trade marks contained cooling agents R 22 included in the HCFC cooling agents group. In accordance with the European parliament and Commission Regulation No.2037/200 dated 29.6.2000 concerning substances causing ozone layer depletion, no HCFC cooling agents may be used in all new devices as of 1.1.2004; the prohibition of their use in service and maintenance will come into force on 1.1.2010 and the comprehensive ban on the use of devices containing HCFC cooling agents will be valid from 11.1.2015.
At what external temperatures are PZP „air – water“ heat pumps able to operate?
The „air – water“ heat pumps can work effectively up to an external air temperature of -20°C in the event of a heating system with heating bodies, or up to a temperature of -25°C in the event of floor or wall heating.
Will not noise from the external unit of the„air – water“ heat pump annoy the neighbours?
The external unit is equipped with ultra-silent fans producing nevertheless some aerodynamic noise. The noise can be diminished by suitable location of the external unit as recommended by the designer or authorised installation company. In addition, the fans operate with two-stage speed regulation which can further reduce the noise during night operation.
Is it possible to use the heat pump in an existing heating system?
Yes, provided the existing heating system is capable to heat the building up to the required temperature when temperature of water entering heating bodies is about 50°C. This can be determined by measurement in the coldest days. We recommend the particular events to be discussed with the designer. In general, gravity heating systems being in most cases oversized meet heat pump demands.
Which is more suitable for the heat pump, a radiator heating system or rather floor heating?
In both cases the heat pump reduces the costs for heating significantly, by tens of per cents. In combination with floor or wall heating operating with lower temperatures the heat pump achieves a higher energetic effect and thus higher savings on the costs for heating.
Is it necessary to procure a buffer tank?
A buffer tank must be used in case the volume of the heating system is insufficient or when heating bodies have thermostatic heads fitted. A buffer tank must be furthermore employed with the heat pump of the „air – water“ system where external evaporator defrosting is done by means of cooling circuit reversation. The necessity of buffer tank installation is to be assessed by the designer of heating.
What is the buffer tank used for?
The buffer tank augments the volume of heating system water which reduces frequency of heat pump switching in the period of excess of its performance. It furthermore provides the function of a so called thermo-hydraulic distributor enabling a constant flow rate through the heat pump and a variable flow rate through the heating system. It is also utilized as a heat accumulator in the „air - water“ heat pumps using evaporator defrosting by means of cooling circuit reversation. The buffer tank is important for trouble-free operation of heating system with the heat pump.
May a gas boiler be used as a supplementary heat source?
Yes. But its connection in the heat pump heating system must be discussed with the heat pump manufacturer or the designer.
Will PZP KOMPLET a.s. ensure borehole making or earth collector laying in the event of „earth – water" heat pump installation?
Yes, the PZP KOMPLET a.s. company has its network of cooperating certified design and installation firms.
Is PZP KOMPLET a.s. a heat pump manufacturer or merely a commercial company?
The PZP KOMPLET a.s. company is a Czech manufacturer of heat pumps. But some heat pump component parts are made by renowned producers, e.g. compressors COPELAND, stainless steel plate exchangers SWEP, axial fans ZIEHL-ABEGG.
Will PZP KOMPLET a.s. ensure the design and installation of the heating system?
Yes, the PZP KOMPLET a.s. company has its network of cooperating certified design and installation firms that will elaborate the complete design of heat pump heating and make the installation.
May a near stream or pond be used as a heat source for the heat pump?
As a rule we do not recommend such combination as either stream or pond water has insufficient temperature to be cooled down directly in the heat pump evaporator in the wintertime. Low-potential heat must be drawn off from water through an inserted circuit containing anti-freezer as with the „earth – water“ system. We recommend the particular events to be discussed with the designer or a certified design company.
Why are two wells necessary when using the „water – water“ heat pump?
In the event of utilization of underground water as a heat source for the heat pump, a considerable quantity of pumped water is required. The water being cooled down is to be returned back into subsoil; it cannot be drained as low-quality surface water as the balance of underground water must be kept
Can an existing well be used for the „water – water“ heat pump?
Yes, provided the well has a sufficient yield and temperature as required by the manufacturer (the values can be found in the design basic documents and leaflets) and if another well is made as the drain one.
May horizontal collectors or boreholes be situated under a house?
It is not recommended to situate any horizontal collectors or boreholes in the vicinity of building foundations and service networks for the reason of possible movements in subsoil due to freezing caused by heat drawing off.
What are the recommended distances from a borehole to a building?
Any boreholes and thermally non-insulated pipes of horizontal collectors shall be routed at a minimum distance of 4 m from building foundations and service networks. In case the primary circuit pipes cross any service networks or building foundations thermal insulation is necessary. The requirement of insulation of primary circuit pipes apply also to pipe entry into a building.
What minimum distance should be between individual boreholes in order not to impair the performance?
The distance between boreholes for heat pumps = 10% of their length.
What is demanded when positioning the external unit of the „air – water“ heat pump?
The external unit is to be positioned in an open area near the heated object. The placement inclusive of surrounding arrangements must provide free air flow over the evaporator. In addition it must be provided draining for the water condensing or freezing-out on the evaporator; the water flows down from it continuously or in icing defrosting. The condensate or defrosted icing flowing down may not become any source of troubles. The external unit shall be technically placed on strip foundations, a hard surface or cantilevers fitted to the building. A recommended distance to the internal unit shall be max.10 m as measured along the cooling agent pipes. Other cases should be discussed with the manufacturer. The placement of the external unit will be recommended by the designer or authorized installation company.
What size of the circuit breaker will be needed for the heat pump?
In this case it is depending not only on the maximum heat pump power demand but also on the maximum demand of the electric boiler used as a supplementary heat source as well as the 100% reserve of heating performance as a rule. We recommend the particular events to be discussed with the designer or a certified design company.
How long is the heat pump life?
It is estimated that the PZP heat pump has a 25 to 30 years lifetime. It is derived from the life of the most stressed parts of the heat pump, namely the used compressor. As against a piston compressor of a comparable performance (the average life of a piston compressor is 15 years as verified by experience) a 2 to 2.5 times longer life is supposed by the COPELAND company for its spiral compressor (SCROLL) due to the compressor design.
What guarantees are provided for the heat pump?
The guarantee period of the heat pump is 5 years.
Is it possible to utilize the heat pump all-year-round, e.g. for DHW warming?
Yes. The most suitable system for all-year-round utilization is the „air – water“ system requiring no shut-down for the reason of collector or borehole recovering as it is in the case of the „earth – water“ system. Moreover, in the transition period or summer time it can work at better conditions – a higher air temperature as against an insufficiently recovered collector or borehole.
Can the heat pump be used for swimming-pool water warming?
Yes. Heat pump use for swimming-pool water warming is very advantageous due to small differences in working temperatures. A significant energetic effect is achieved here by the heat pump. The most suitable heat pump is that of the „air – water“ system from the reasons mentioned in the previous answer.
What are the savings when using the heat pump?
When using the heat pump in its bivalence connection, costs savings will be about 65% (as compared e.g. with a directly heating electric boiler).
