Leading heat pump manufacturer Mitsubishi Electric has released a new technical supplement showing how to design and calculate the heat loss on a new-build property, and the factors and considerations needed to complete the project successfully.
“We produce lots of case studies on our Ecodan range but new homes have different requirements to retrofit situations, so we saw a lot of sense in taking people through the process with a live project,” explains Max Halliwell, product marketing manager for the company’s Ecodan range of air source heat pumps.
This makes the space heating requirement much lower that the hot water energy need and calls for a heating system that is able to cope with hot water production as the dominant load.
Mechanical heat recovery ventilation (MVHR) and PV systems on the roof give the 164m2, two-storey property a peak heat loss of just 3.8kW, so it needs far less heating that a traditional British home, placing a different requirement on the heating.
The building’s fabric U-Values include 200mm insulation board in the floors; timber-frame wall construction with mineral wool insulation; 350mm insulation in the roof; and double-glazed windows.
The home has three bathrooms with underfloor heating throughout the ground floor with traditional radiators providing heating to the bedrooms.
“The system is designed with heat loss calculations set at an ambient temperature of -3°C, and has a design set-point of 21°C for the ground floor, 22°C for the bathrooms and 18°C for the bedrooms,” explains Halliwell.
The answer the different requirements of this home, an Ecodan QUHZ system is used, offering a capacity of 5.2kW at the design ambient temperature, exceeding the building’s heat loss and making the QUHZ eminently suitable for the property.
Installing the Ecodan QUHZ has helped the home achieve an A rating (92/100) on the energy performance certificate (EPC).
Using CO2 as the refrigerant means the QUHZ can ensure a large delta T of 13.1 in this installation to maximise its efficiency. It also operates with a peak design flow temperature of 50°C, and a system flow rate of 4 l/min.
The system delivers water at 70°C to a packaged 200 litre a thermal store. From here, mains water is heated directly up to 65°C using a unique plate heat exchanger, effectively giving the family hot water on demand.
The QUHZ model also offers exceptional noise levels with a whisper quiet 41.2 dB(A) at 1.5 metres from neighbouring properties, making it ideal for almost any new-build scenario.
The renewable heating includes automatic in-built energy monitoring using Mitsubishi Electric’s MELCloud internet-based system, which allows for full control from anywhere in the world.
“We’re confident that this is a heat pump system suitable for almost any property and have designed the QUHZ specifically to match the different requirements of new-build,” ends Halliwell.