How ground source heat pumps can save and make clubs money
8th January, 2012 by Jenny Yu
When Pyecombe Golf Club near Brighton needed to replace an ageing LPG water heater and electrical central heating system in its clubhouse last year, the club wanted to take the opportunity to reduce both its energy costs and its environmental impact.
With so many different options available, from hydroelectricity to micro-combined heat and power, from solar water heating to wood-fuelled heating, the club commissioned a free environmental and energy assessment from the West Sussex Sustainable Business Partnership, which came up with solutions including one surprisingly uncommon at British golf clubs: ground source heat pumps.
Ground source heat pump systems are visibly unobtrusive – as the heat-collecting loop is underground and the pumps and all other equipment that go with it can be located out of sight in the clubhouse’s existing boiler room.
How do heat pumps work?
The pipes in the ground loop system contain a mixture of water and antifreeze, which is pumped around underground at a low temperature, thus collecting free, renewable heat energy into the ground pipe fluid. This part of the heat exchange occurs often below zero degrees Celsius. The ground pipe fluid then enters one side of the heat pump and exchanges its heat into a low-temperature refrigerant fluid circulating inside the heat pump, causing the refrigerant to boil and become a gas.
The temperature is still very low at this point but free, renewable heat energy has been transferred into the refrigerant inside the heat pump. The refrigerant gas then enters a compressor, and, as the gas is compressed, its temperature rises dramatically to a level hot enough to heat radiators, underfloor or warm air heating systems and the hot water cylinder in the clubhouse.
After giving up its heat energy, the refrigerant pressure is reduced through a throttle valve and it becomes a low-temperature liquid again, before circulating back through the evaporator side in a continuous loop.
This is how the ‘free’ heat collected at very low temperature on one side of the heat pump is converted to high-grade heat on the other side.
“The ground heat collector pipes can be laid in horizontal trenches about 1.2 metres deep, or in vertical boreholes drilled down into the ground as at Pyecombe Golf Club,” said Mike Reynell, general manager for Ecovision in the Southeast. “The length of the ground loop depends on the amount of heat required. It is crucial to size the ground collector correctly because if too much heat is extracted from one region, conditions comparable to Siberian permafrost can be created underground. This will dramatically reduce the efficiency of the heat pump as it struggles to transfer heat from the already-frozen ground.”
Pyecombe Golf Club
The club received the maximum grant from the now-closed Low Carbon Buildings Programme, plus an interest-free loan, repayable over two years, from the Carbon Trust, to fund the installation, which cost, including a complete ‘wet’ system of new radiators, just over £80,000. Ecovision selected the heat pump (made by Dimplex) and designed the ground loop, and installed both. The club was fortunate in having one member who owned an electrical contracting company (A J Taylor) and another who owned a heating engineering company (KC Contracts (Sussex)), which designed and installed the electrical installation and the central heating system respectively, with the latter installing convector heaters manufactured by Biddles.
The ground collector loop was run in seven boreholes located in a field adjacent to the clubhouse and the entire system was built and operational in a few months, opened by Keith Taylor MEP, a member of the Green Party. Pyecombe has stated that the system, which provides hot water for showers, hand basins and kitchen use, and the new system of radiators, has cut its heating consumption by over a third as well as reducing its CO2 emissions. This means that Pyecombe is making significant annual savings and can expect to cover the extra capital costs of the heat pump installation over a straight replacement of its old system within 10 years.
Chris Openshaw, a retired engineer and a former captain of Pyecombe, who was part of the in-house project management team, said other golf clubs have contacted him for information since the installation, and they could both benefit and learn from Pyecombe’s approach: “Solar and wind energy systems on their own would not have met our club’s demands. However, this heat pump system has reduced our dependency on fossil-fuel-produced energy.
“It should be noted though, our approach for doing this was not sustainable; it was financial. We are a long established golf club who had a system that had to be replaced and wanted the most cost effective way of going about it. Other energy-saving measures have also been installed, such as improved building tightness, movement-detection light switches, extra insulation and reduced-flow shower heads, the latter also thanks to a grant.”
Maintenance
“Very little maintenance is required if a well-designed heat pump system is installed properly,” said a spokesman for the Energy Saving Trust (EST). “Equipment should operate automatically with little noise – the only system noise is from the small circulation pump which, if audible at all, should be no louder than a modern central heating pump. Life expectancy for the heat pump is around 20 years with a component replacement required, while the ground loop system should last over 40 years. A yearly check by a member of staff at the golf club and a more detailed check by a professional installer every three to five years should be sufficient.
“In addition, there is no boiler [they can be used in addition to a boiler or as an alternative] or fuel tank, no flue or ventilation requirements and no combustion or explosive gases.”
Things to consider
According to the EST, other things to consider before installing ground source heat pumps include the current energy efficiency of the clubhouse. “Heat pumps are most efficient when used in highly insulated buildings and are most likely to save money and carbon dioxide when they are used to replace electric, LPG or coal heating systems,” said the spokesman. “They work better with slow response, low temperature heating systems such as under-floor heating rather than conventional wet radiator systems. They are most efficient if they provide heat over a long period of time to a heating circuit that runs at around 35 to 55 degrees Celsius.”
Golf clubs have to be able to cope with sudden surges in demand for hot water when dozens of players need to shower after a competition. However, this demand can be met by increased storage and / or the option of a heat pump capable of generating higher water temperatures when required. Heat pumps can be combined with both solar hot water and photo-voltaic systems to provide hot water or electricity. Additional top-up or back-up heating can be obtained from an immersion heater, although this reduces the savings.
Golf clubs also need to check that their electrical supply is suitable to power certain types of heat pumps; multiple pumps may be an option, while some pumps are available with a ‘soft start’ option if the supply is inadequate. A heat pump system should also be connected to its own breaker in the fuse board.
Heat pumps need electricity to run but the heat they extract from the ground is constantly being renewed naturally and the pumps use significantly less electrical energy than the heat energy they generate. “Typically, you only need one unit of electricity to deliver two to three units of heat with a heat pump,” said the EST spokesman. “Furthermore, you could be paid to produce the heat under the government’s Renewable Heat Incentive (RHI), which guarantees payments for 20 years, provided the pumps were installed by an MCS-accredited installer. The RHI went live at the end of November so now is the perfect time to take advantage of this generous scheme.”
Halmstad Golf Club
The technology is common in Europe and Halmstad Golf Club in Sweden, which hosted the 2007 Solheim Cup, was able to deploy it in an enhanced way to Pyecombe when it extended and renovated its clubhouse recently.
The club, like Pyecombe, did not want to use a major area of its course or grounds to store the system, despite having a large clubhouse, and, due to warm summers, the club was also keen to use the system to cool the clubhouse during certain parts of the year.
“As is common with older golf clubs [Halmstad was built in 1935], the solutions to the various technical requirements of the clubhouse had started living a life of their own and became rather diversified.
“So when the time had come to renovate the clubhouse it was natural to install a completely new heating system at the same time,” said Claes-Uno Nilsson, who project managed the installation.
“Previously, the club used to have a variety of heating systems, including oil and electricity.
“In Sweden today, the central heating in commercial properties is generally speaking either district heating or heat pump systems. And heat pumps are taking a bigger and bigger share of the market.”
When Halmstad rebuilt the clubhouse, it used boreholes to install the heat pump system. “We could just as easily have chosen a system using shallow ground source heat. But considering that this is a golf club, we wanted to interfere as little as possible in the production – in other words, the playing of golf,” Claes-Uno explained. “That’s why we decided to drill instead of dig – to ruin as little as possible of the fairway.”
Furthermore, the system cools the building down when it is too hot.
“Using a heat pump system for cooling gives you an extremely cost-efficient solution,” said Claes-Uno. “And at the same time you’re storing heat in the bedrock for the coming winter.
“This concept is called ‘free cooling’ and it means that the heat pump compressor is not in use – only the circulation pumps. The cooling medium in the pipes from the boreholes is led straight into the building’s cooling system, either through the ventilation system or through separate fan convectors. The warm indoor air is passed across the pipes containing the ‘cool fluid’, thereby falling in temperature. The now slightly warmer cooling medium is then recirculated down into the borehole where it is cooled again, before being returned up into the cooling system.”
In terms of maintenance, problems are usually fixed before any members, visitors or staff have even noticed them: The system is connected to an alarm centre and is constantly monitored, ensuring that all the measurement data is stored. Any irregularities in the functioning of the system trigger an alarm that alerts the technicians at the alarm centre, who can deal with the problem.
From southern England to northern Europe, golf clubs are finding new, innovative and cost-efficient ways to heat themselves this winter.