Richard Prince at Advance Appliances provides some insight into the use of Heat Pump Cylinders.
Q. Can an existing cylinder be used with a Heat Pump, or is a specific Heat Pump Cylinder required?
Heat Pump Cylinders are designed and manufactured specifically for use with a Heat Pump, taking into account the different flow and return temperatures and power outputs available from Heat Pumps they require specific coils or heat exchangers to work efficiently. If you are installing a heat pump and not replacing a cylinder designed to work with a conventional boiler it will cause inefficiencies within the system and lead to a poor hot water supply.
Q. What kind of hot water temperatures can be achieved from a Heat Pump Cylinder?
Typically, you will achieve a stored water temperature of around 50°C when using the heat pump supply, however we are seeing more and more high temperature heat pumps entering the market which will heat stored water to above 60°C.
Cylinders will have a secondary heat source to ensure a pasteurisation cycle can be carried out, these are normally Immersion Heaters which can also be connected to the grid or solar divertors to heat stored water up to and above 60°C if required.
Q. What is the difference between a single coil cylinder and a twin coil cylinder?
A standard single coil Heat Pump Cylinder will have a large surface area coil for connection to the heat pump, coupled with a secondary heat source for the pasteurisation cycle. Products are also available on the market with a secondary coil, these are typically coils to be connected to solar collectors and usually in the base of the cylinder.
The secondary solar coil allows for heat to be supplied via a renewable means typically throughout the summer months, during high solar gain periods you can heat a cylinder entirely from a solar collector array.
Q. Are there any particular installation issues to be aware of when fitting a Heat Pump Cylinder?
Heat Pump Cylinders are typically Unvented Cylinders connected to a heat pump rather than a conventional boiler. All building regulations must be followed as required when fitting an Unvented Cylinder as shown in Part G3. The hot water cylinder is installed in exactly the same way just connected to a different heat source and may have some additional electronic controls for the specific heat pump manufacturer.
Q. What kind of warranties are available?
You will find different warranties out in the market when shopping for a heat pump cylinder, some manufacturers offer extended warranties on their premium products and some warranties are defined due to the materials used in manufacturing. Most warranties on the market today will be set at 25 years for a stainless steel heat pump cylinder.
