Christopher French is freelance writer on renewables/water/wastewater. French can be reached at [email protected].
In 1992, when the American golf course designer Rees Jones included four lakes as part of his plan for The Oxfordshire in England, even this architect may not have conceived just how significant that water was going to be. In less than three decades, water from just one lake is set to make a significant positive breakthrough for the environment and make a notable benefit to the bottom line of The Oxfordshire business.
Freedom From Utility Bills
Instead of being at the mercy of utility bills, The Oxfordshire’s General Manager Ryan Bezuidenhout was determined to find a way to reduce energy costs. He set out to increase profits by 30%.
“For me, and with the backing of our owners (Leaderboard Golf), the way forward was to see what could be achieved with an alternative and sustainable energy solution so that we could free ourselves from those ever-increasing utility bills,” Bezuidenhout said.
Was there a catch? With new building there is an opportunity to be innovative. Regulations call for far more in the way of energy efficient products and solutions. But a retrofit?
Enter Geyser Thermal Energy, and its founder and CEO, Lolli Olafsson. When it comes to recycling, those three ‘Rs remain very valid; Reduce, Reuse & Recycle. For an energy retrofit, Olafsson’s modus operandi is to first see how energy consumption can be reduced, calculate future loads and then look onsite to see what energy sources are available.
Just as at home, we could all find ways to save energy, the first stage sounds simple, perhaps, but then we do not have commercial pressures of paying guests to keep happy. Rather than leave the heating and cooling of hotel rooms on permanently, it was decided to switch to manual control, whereby guests would control the temperatures of their rooms.
“Keeping guests happy is paramount,” Bezuidenhout said. “But having air conditioning or heating blasting away all day and night just is not necessary, especially when it only takes 20 minutes to regulate and maintain a desirable temperature.”
To stop staff changing public area temperatures, thermostatic radiator valves (TRVs) were installed on the radiators and set at 68°F. Since this initiative was introduced, including staff inspecting rooms after check-out to ensure that everything is switched off, there have been no complaints from guests and 11% has been shaved off energy consumption.
Trying to calculate future energy loads and establish a level for energy use was certainly a challenge for Geyser Thermal Energy. The Oxfordshire kept occupancy reports and a record of oil consumption, and while overall use of electricity was predictable, energy use was not monitored for different buildings. With savings based on oil consumption, savings created due to the reduction in energy being used by the plant had not been included. Also, the air handling units (AHUs) were modified to operate on lower temperatures, so heat pumps can be used instead of boilers. This saves on energy because running AHUs at higher temperatures would require the heat pumps to use more electricity.
Energy Retrofit
Back in 1992, golf course architect Rees Jones blended the natural countryside into his inland links design with four lakes that also would serve as an irrigation system for the greens. The main lake is now key to a closed-loop water source heat pump system, as part of a $650,000 energy retrofit, designed by Geyser Thermal Energy.
Pumping water up from the lake to the plant room’s heat exchangers will, in time, replace The Oxfordshire’s oil-fired boilers and chiller with a low-energy heat pump system, connected to a 250kW solar unit installed onsite. Payback is expected within five years. The design will immediately reduce the high-energy boiler and chiller use from more than 1,500kWh to under 100kWh.
“We considered introducing a ground source for the heat pumps, but the ground loops would have taken up too much space where the PV array (photovoltaic system) is set to be installed,” Olafsson said. “That said, for the low-temperature heat network, the lake water was an obvious choice because it absorbs heat much more quickly than earth and is quick to replenish”.
Historic lake temperature data proves that there is low risk of the lake freezing, according to Olafsson. The lake’s temperature is around 45°F in the winter, but if necessary, heat can still be removed if the temperature goes down to 37°F. Six 3.5-inch pipes at 2 feet depth will run from the lake to the hotel between the course’s holes so that golfers will not be inconvenienced by the trenches during installation.
Low Temperature System
The retrofit at the golf course is a low temperature system. Flow temperatures for the heating are 122°F/113˚F and 140˚F/131˚F for the hot water. This minimizes heat losses through the pipework and allows more economical plastic pipes to be used than steel. There is scope to utilise heat from other sources, such as the heat generated from cooling, into the ambient network, Olafsson said. Geyser Thermal Energy opted for a closed loop, rather than open water loop, partly because it would require far less maintenance, and therefore less ongoing costs.
“So long as the water is well maintained, a closed loop in which the circulation pumps are the only moving parts, is far more reliable, whereas an open system can present issues with filtration,” Olafsson said. “We are also reducing peak loads that will enable The Oxfordshire to benefit from much cheaper off-peak electricity by introducing buffer tanks for both hot and cold water. Without the buffer tank – based on a heating system set up for peak loads for an hour a day, you might have a system that is 50% larger, which is totally unnecessary.”
The building management system also has been upgraded so that personnel can better understand how the system works and see what the loads are in the swimming pool, spa and for the air conditioning.
