Commercial heating applications are more varied and complex than domestic heating applications, and likewise commercial heat pumps are more varied than their domestic counterparts.
It is essential to always choose the correct type of product for the specific application. Choosing a heat pump which is over-specified may be prohibitive from a capital cost point of view. Choosing one whose abilities do not meet the requirements of the application may bring problems satisfying the demand or meeting the Irish regulatory requirements.
The diagram below gives an overview of the typical operating ranges of various types of commercial heat pump, and an indication of which applications they are most suitable for. A further breakdown is given in the sections following.
Low or medium temperature applications - small capacities
For applications with underfloor heating (35°C), fan coil radiators (45°C) or medium temperature radiators (55°C), requiring heat pump capacity not exceeding 100kW approx, it is normal to use a cascade of small monobloc heat pumps (<=20kW). The heat pumps are sometimes supplemented by boilers in a "hybrid" type system.
This type of heat pump usually contains an inverter driven reciprocating scroll compressor and inverter driven fans. They are very similar to a domestic heat pump but in larger capacities and usually utilise a three phase electricity supply.
These types of products are classified as "Heat pump Space Heaters" according to Ecodesign regulations. This means both 35°C and 55°C Ecodesign performance data is published and so these products are suitable for entry into DEAP or NEAP energy assessment software for either low (35°C) or medium (55°C) temperature applications.
Low temperature applications - larger capacities
The majority of commercial heat pumps will be suitable for use in low temperature (35°C) applications, however it is appropriate to choose a product designed for the application as this will minimise capital cost.
Most larger capacity commercial heat pumps use non-inverter single or multi-step scroll compressors.
The most appropriate heat pump for large low-temperature installations is a "Low temperature" heat pump according to Ecodesign. This type of product has been designed to operate at lower temperatures and forgoes any additional technology to extend their operating range beyond what is necessary.
While this class of heat pump may be able to provide 55°C+ flow temperatures in milder weather, they will not be able to achieve these temperatures during the minimum temperatures experienced during an Irish winter.
From a regulatory point of view, these products may not be entered on NEAP building energy rating software for the standard design temperature of 55°C as the 55°C Ecodesign data is not and cannot be made available. This means they could not comply with Irish building regulations in medium temperature applications.
However, they are perfectly suited to underfloor heating (35°C) or fan coil radiators (45°C) and offer an excellent cost-effective way of heating these applications while meeting the requirements of the building regulations.
Medium temperature applications - larger capacities
Medium temperature applications refer to applications where a 55°C flow temperature is required. For example, a building whose heating is served by medium-temperature radiators.
In these applications, the most suitable products are classified as "Heat pump Space Heaters" under Ecodesign. This means both 35°C and 55°C Ecodesign performance data is published and so these products are suitable for entry into DEAP or NEAP energy assessment software for 55°C applications.
This type of heat pump is generally suitable for use on lower temperature applications but they have a specific design to make them suited to medium temperature applications . These optimisations extend their operating range beyond that of a low-temperature heat pump, while ensuring compressor reliability at higher temperatures. For example, liquid or vapour injection technology is typical. Usually compressors are multi-stepped and/or multi-staged to provide better load matching.
By way of example, the Thermocold Mex/Domino EXR are capable of supplying 65°C down to -10°C outside an 55°C down to -20°C outside.
A "low-temperature" heat pump should not be considered for this application as it does not have sufficient operating range or the regulatory certification required.
Very High Temperature applications
Very high temperature applications refer to applications which demand flow temperatures in the region of 70°C-80°C.
A Very High Temperature Heat Pump will be designed to meet these higher temperature needs. Semi-hermetic reciprocating compressors in either single or multi compressor configuration will typically be paired with a technology such as liquid injection to manage the high temperatures inherent in the refrigeration circuit. Without measures such as these, a heat pump would be unable to reliably deliver the high temperatures required.
The ideal application for this category of heat pump is the replacement of existing boiler plant while retaining the original heat emitters (e.g. very high temperature radiators). This is attractive where the works required to install lower temperature emitters would be difficult or cost prohibitive.
Low GWP applications
GWP stands for Global Warming Potential and is a measure of how damaging refrigerants would be to the atmosphere if they leaked or were released into the environment. The GWP of standard refrigerants today typically ranges between 500-2500 - which means releasing a kg of refrigerant would be as damaging as releasing 500-2500kg of CO2.
R290 (propane) is a refrigerant with a GWP of just 3 meaning its potential environmental effects are very small. This makes it an excellent choice for applications where environmental sustainability is among the primary considerations.
The operating range of a R290 heat pump is similar to a heat pump space heater. It is suitable for use on medium and/or low temperature applications.
Due to the nature of R290 (Propane) refrigerant, some special precautions are taken. The use of ATEX certified components within the compressor compartment, sealing of the compressor compartment and extraction fans coupled with a refrigerant leak detector are all methods used to ensure safe operation. In the case of the Enerblue Purple HP, the benefit of this additional sealing are reduced noise operation as standard.
Water Heating using CO2 heat pump
A CO2 heat pump is a good solution for heating water in applications where there is high daily hot water usage.
The Enerblue HP90 heat pump is paired with a number of large volume hot water cylinders which are heated in series. When the bottom of the final cylinder is hot, the heat pump switches off. This strategy allows the heat pump to run for long periods at high efficiency while also providing a large volume of stored water at 80°C+, giving ample supply of water when needed. This high temperature also provides excellent legionella control.
The CO2 cycle operates at much higher pressures than a standard heat pump and a gas cooler is used instead of a condenser. The lower the inlet temperature to the gas cooler on the hydraulic side, the greater the cooling that is achieved and more energy is absorbed from the outside air. This makes a CO2 heat pump an excellent choice for heating domestic hot water from cold.
An added benefit is that CO2 is a natural refrigerant with very low global warming potential. This means that the small volume of refrigerant within the heat pump would have very little effect from a climate point of view it it were ever released into the atmosphere.
RVR Energy Technology can supply commercial heat pumps for most applications. If you have an application in mind, please contact us.
The Immergas Magis Pro three phase heat pumps are useful in smaller applications. Follow the link below to learn more.
Thermocold provide a wide range of commercial heat pumps ranging from smaller capacities to very large models. Four pipe and Six pipe options are also available, as well as a complete range of chillers. Follow the link below to learn more.