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Typical Installation Schematics The following section includes typical schematics of how a heat pump can be connected. Only the load side is shown i.e. the heating distribution system. It is important to note that the schematics are only general arrangements and hence do not illustrate all required valves or fittings. They are only a guide and should not be used as full installation plans. Domestic heat pump with underfloor (single manifold)
Kensa Compact heat pumps have inbuilt water pumps for both the ground and the heating distribution circuits. The water pump for the heating distribution circuit is sufficient to provide enough flow and pressure for underfloor distribution systems comprising of a single manifold. Additional pumps should not be required. Buffer tanks are not required if 25% of the underfloor zones are left hydraulically open. These open zones are generally areas such as halls and bathrooms. Thermal mixing valves should be removed from the underfloor manifold if fitted. Kensa would always recommend fitting an expansion vessel on the heating distribution circuit.
Domestic heat pump with underfloor (more than one manifold)
Due to the pressure and flow requirements of the underfloor circuits each individual manifold should have a small circulating pump. The integral heating distribution pump in the heat pump circulates water around a shunt loop (ring main). Each underfloor manifold pump then draws water as required from the shunt loop. Buffer tanks are not required if 25% of the underfloor zones are left hydraulically open. These open zones are generally areas such as halls and bathrooms. Thermal mixing valves should be removed from the underfloor manifold if fitted. Kensa would always recommend fitting an expansion vessel on the heating distribution circuit.
Domestic heat pump with underfloor systems (fully controlled zones)
For heating distribution systems, which require each zone to be fully controlled, Kensa would recommend fitting a two connection buffer vessel. This will avoid any short cycling problems that could occur at low load conditions. Thermal mixing valves should be removed from the underfloor manifold if fitted. Kensa would always recommend fitting an expansion vessel on the heating distribution circuit.
Domestic heat pump with radiators.
When operated with radiators and to avoid short circulating problems, one bypass radiator should be left ‘open’, i.e. any TRV is removed. This radiator can be positioned in areas such as halls or bathrooms. It is important that the heat pump has been specified as operating on radiators, as a higher outlet temperature will be required and a ‘smart start’ is necessary to limit any electrical disturbances caused by the compressor starting. Kensa would always recommend fitting an expansion vessel on the heating distribution circuit.
Domestic heat pump with domestic hot water via an indirect tank.
Under normal conditions the heat pump will provide heat for the underfloor distribution system at an ideal temperature of 35°C. When there is a demand for DHW the three-port valve diverts the flow from the underfloor distribution circuit into the indirect coil. The temperature of the water from the heat pump is raised to approximately 50°C. When the required temperature is reached within the tank, the three port valve switches back to the underfloor distribution and the temperature drops back to 35°C. If this scheme is being considered, please contact Kensa for additional details.
Commercial Plantroom heating or cooling
Click on the drawing for further details of plantroom models in heating or cooling applications. Commercial plant is supplied in modules which are linked together. They do not come with integral water pumps, these are generally sized by the M and E consultant. The modules can be set for either heating or cooling (if specified as a reverse cycle module) and the schematic above can be used for both modes of operation. Heating and cooling together cannot be achieved using the system design as above. The effectiveness of the cooling (and heating) will depend on the heat distribution system and generally for cooling Air Handling Units are used. In commercial applications buffer tanks are sometimes required, due to the large variation of loads and turndown issues. In this case Kensa would generally recommend a two connection buffer tank installed in the heat pump return, after the low loss header. This will allow the required flow rate to be maintained through the heat pump and keep a sufficient volume of water 'in circuit' to prevent short cycling. This enables the heat pump to cope with low load conditions, while not introducing any inefficiency associated with indirect buffer tanks.
Commercial Plantroom heating and cooling
Click on the drawing for further details of plantroom models in heating and cooling applications Commercial plant is supplied in modules which are linked together. They do not come with integral water pumps, these are generally sized by the M and E consultant. The modules can be set for either heating or cooling (if specified as a reverse cycle module) and the schematic above can be used if heating and cooling is required at the same time. By using diverting valves, a single module (or more) can provide cooling, while the other units provide heating. The effectiveness of the cooling (and heating) will depend on the heat distribution system and generally for cooling Air Handling Units are used. In commercial applications buffer tanks are sometimes required, due to the large variation of loads and turndown issues. In this case Kensa would generally recommend a two connection buffer tank installed in the heat pump return, after the low loss header. This will allow the required flow rate to be maintained through the heat pump and keep a sufficient volume of water 'in circuit' to prevent short cycling. This will enable the heat pump to cope with low load conditions, while not introducing any inefficiency associated with indirect buffer tanks. For other configurations or further details please contact Kensa Technical Department. |
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