The importance of correctly sizing a heat pump
In essence, the output of a heat pump system and how it delivers its capacity is central to the inverter vs fixed output debate. To understand and appreciate the performance benefits offered by an inverter heat pump, it’s important to understand how a heat pump is sized.
To determine the size of the heat pump needed, heat pump system designers calculate how much heat the property loses and how much energy is required from the heat pump to replace this lost heat through fabric or ventilation losses in a building. Using measurements taken from the property, engineers can determine the heat demand of the property at outside temperatures of -3oC. This value is calculated in kilowatts, and it’s this calculation that determines the size of the heat pump.
For example, if the calculations determine the heat demand is 15kW, a heat pump producing a maximum output of 15kW is necessary to provide heating and hot water to the property year-round, based on the current room temperatures required by BS EN 12831 and the projected minimum temperature for the area, nominally -3oC.
The size of the heat pump is significant to the inverters vs fixed output heat pump debate because when a fixed output unit is installed, it will be running at its maximum capacity when switched on, regardless of the external temperature. This is an inefficient use of energy because 15 kW at -3oC may only need 10 kW at 2oC. There will be more start – stop cycles.
An inverter drive unit, however, modulates its output across a range between 30% and 100% of its maximum capacity. If the heat loss of the property determines a 15kW heat pump is needed, an inverter heat pump ranging from 5kW to 15kW is installed. This would mean that when heat demand from the property is at its lowest, the heat pump will work at 30% of its maximum capability (5kW) rather than the 15kW used by a fixed output unit.
Remark：
Some of the articles are taken from the Internet. If there is any infringement, please contact us to delete it. If you’re interesting in heat pump products，please feel free to contact OSB heat pump. We are your best choice.