Heat pumps can help businesses cut their heating costs. Cliff Arnold explains how
It's not just homeowners that are hit by rising energy prices. The profits of large commercial and industrial businesses can be affected too. This is forcing usinesses to look at renewable technology to heat their premises.

Their criteria are simple; they need technology that reduces their energy use and offers a decent return on their investment. Ground and air source heat pumps tick both boxes.

Any business looking to invest in a heat pump will expect a survey and an initial consultation with a contractor who is able to explain and design a bespoke heat pump system for their specific needs. The benefits of a heat pump will never be enjoyed in a building that has no heat retention measures in place. Make sure your customer understands this. Any money spent on upgrading cavity wall insulation, double glazing or draft proofing can save money on the capital cost of a heat pump system.

Before fitting an air source heat pump you need to know the local mean average temperature of the site during the summer and winter. Colder areas will need a bigger heat pump. The Met Office is a good place to find local mean temperatures. This will give you the basis for the heat pump design.

Get to grips with peak heat load

Make sure you get to grips with the peak heat load for whichever building the air source heat pump is to be applied too. If the outside temperature is below freezing the heat pump needs to be able to absorb a certain amount of low grade energy to maintain the internal temperature efficiently. The size of heat pumps is critical.

Any obstruction or fouling of the air flow to the unit will reduce the heat pump's effectiveness to extract heat from the air. Ideally you want a secure location, which can provide air flow to the heat pump unit. Somewhere that gets sunlight is the best place for installation.

Installing a system buffer vessel, whether you have a fix speed or inverter driven heat pump, reduces cycling of a heat pump's compressor. This design feature increases heating performance and seasonal COP (coefficient of performance).

Build a stable platform for the heat pump to be mounted upon to prevent any slip hazards during cold weather. Include a run-off incline and a soak away or fit a condense tray, so condensation drains away safely.

All heat pumps have an inbuilt requirement to defrost the evaporator in cold weather. This ensures the heat pump continues to run efficiently. Any insulation needs to be protected to stop birds and rodents chewing at it, which would result in a reduced energy transfer and loss of produced heat. So keep insulation covered and protected, which will also offer further protection from snow fall. Even though solar facing locations are best for installation, the UV from the sun can actually damage and reduce the thermal qualities of insulation. So don't scrimp on the quality of insulation.

Most heating systems use radiators or fan coils and they would have been sized accordingly for a fossil fuel boiler at the time of installation. Don't assume that is still correct. Heat pumps work at different temperatures to boilers so the radiators will possibly need to be re-sized. If the surface area of a radiator isn't increased to match the room heat requirement, the flow temperature will have to be increased, which in turn will reduce efficiency.

Larger, higher performing radiators will increase seasonal performance with any heat pump. Ground source heat pumps use pipes, known as ground loops, which are buried in the earth in order to extract low grade heat from the ground.

The quality of the energy transfer in the ground loop depends on the consistency of the soil beneath the surface. Wet earth offers better conductivity than dry earth. So water permeable or porous soil, which water and rainfall can flow through, will give an energy transfer greater than a dry, solid substance like clay. Find out what the soil is made up of at least one metre below the surface before sizing the loops for the ground collector. Even if you've haven't visited the site you can still make a start by researching online.

Landis (Land Information System) has a soil scape map showing the 28 different soil types found across the UK. You can search soil type by postcode. Take Droitwich Spa, where CTC is based, as an example - most of the town is on loamy clay soil, which would give a lower energy transfer, over Fairfield, which is a mile or two north where the soil is peaty permeable and wet, which would give a far better energy transfer. Obviously, these tools are no substitute for an actual survey, but they demonstrate just how diverse the soil in the UK is.

If you do find dry clay beneath the earth it doesn't mean a ground source heat pump is out of the question - you can improve the energy transfer of the ground. This can be done by increasing the surface area of the ground collector. Also installing the building's soak away from the property's gutters over the ground loops you can increase the energy yield. Just make sure the drainage is equipped to prevent any potential water build up.

If you're working in a limited space you can still install a pump with a vertical or radial borehole system instead of ground array. The Ground Source Heat Pump Association has plenty of advice on installing vertical borehole systems on its website.

There are further options if digging straight down is not possible. I have known cases where the installer has drilled diagonally into the ground instead. A borehole system will give you a better energy extraction rate without having to install extra drainage around your ground loop area. Thermally enhanced grouts are available to improve the energy transfer too. By following a methodical process you ensure your customer gets what they need - an energy efficient solution that means heating costs don't eat into their profits.

// The author is general manager of CTC //