Getting the most out of newly specified ground source heat pump systems
Based on Dimplex’s recent CPD, ‘Hydronic Distribution’, Christian Hadley, installed product marketing manager, Dimplex, highlights four key factors for good plant room design when installing a commercial ground source heat pump.
Plant room space
It is of course simple to design the plant room to the specific needs of a new system, but for retrofit projects, it is important to consider the space requirements of the new equipment.
Dependant on the configuration of the heat pump system, you may need buffer tanks or higher capacity hot water storage tanks. It is also important to consider how large these are and whether you have enough space in your proposed plant room.
Remember to consider the logistics of actually installing the new equipment in the existing space. In some cases it may be easier to build a new “energy centre” to house the new heat pump system.
Best practice and regulations
As ground source heat pumps utilise the same technology employed in commercial refrigeration, there is a level of best practice that should be incorporated into the plant room design. This will ensure the heat pump system meets sustainability targets and building regulations.
Although ground source heat pumps are a low maintenance solution for heating systems, some models do require annual refrigeration checks to comply with F-Gas regulations. This often involves removing panelling to get at the internal pipework, so it is also important to consider the access points in the plant room.
Heat pump systems normally consist of the heat pump, a cylinder and buffer tank, plus the usual hydronic distribution equipment. As some of the equipment, such as the compressor, is very heavy, it is important to gauge whether the existing plant room floors can support this weight or if any reinforcement is required.
Ground source heat pumps, unlike boiler systems, work far more efficiently at a lower temperature so the heat emitters may need to be upgraded to ensure that with a low flow temperature it can still provide the desired heat output. Also the flow rate from a heat pump, compared with a boiler, is often higher, requiring larger pipes and pumps. Building engineers must therefore consider ways of mitigating this in the system, for example, the use of bypasses, headers and buffers permitting the design of variable flow systems.
In addition, whilst the noise and vibration emitted by the compressors units can be reduced to an extent, this cannot be fully eradicated. It is also important to consider the impact of vibration in the design of the pipework and throughout the installation.
BREEAM – earning credits
Ground source heat pumps are well placed to meet the requirements of BREEAM too, the commonly-used points-based assessment method for both new build and existing commercial buildings. It is a standard of excellence which is coveted but not unobtainable thanks to the continued development of renewable technologies such as ground source heat pumps.
With good design and planning of the plant room and hydronic system, credits are available in the ‘low and zero carbon technology’ sub-category, as well as ‘energy monitoring’ as Dimplex’s ground source heat pumps can also be metered and connected to a BMS. Perfect for commercial engineers seeking to deliver low-cost, low carbon heating for offices, schools and hospitals to meet required levels of efficiency and contributing significantly to high BREEAM scores for those buildings with additional sustainability targets.