There are three commonly used techniques in pool ventilation energy saving:
• Varying the level of fresh air in the total ventilation with motorized dampers (VFA)
• Dehumidification of pool leaving air to allow its recirculation (DH)
• Heat Recovery (HR) from air discharged, usually by a Plate Heat Exchanger
VFA is the most powerful of these techniques, it can save 95% of sensible with the pool cover in place. We use it in all our systems. Either DDH or HR can be added to bigger systems. The law of diminishing returns needs to be carefully watched. Adding the third technique provides little saving from the balance of energy after using two. Also very important, is the extra fan motor electricity required, which is considerable in relation to the use of Refrigeration DH and limits the saving from HR.
A key aim of pool hall ventilation is to cut the cost of gas and electricity involved.
A middle sized public pool can have an annual energy bill, at current tariffs of more than £80,000, if there is no energy conservation in the ventilation equipment. This is the result of the high temperature and ventilation rate required to absorb evaporation and maintain comfortable temperature and humidity levels, combined with the need to keep the system in operation twenty four hours per day.
The bill for a middle sized public pool, without energy conservation is as follows:
||Heating ventilation air then lost to atmosphere
||Energy used in the evaporation of pool water
|Fan motor electricity
||Electricity use of motors driving ventilation fans
Some important points follow from these figures. Sensible energy accounts for 75% and is the most important priority in energy saving. 45% of latent energy can be savedwith a pool cover. Fans selected need a high efficiency; lower efficiency fans can add 50% to this cost.
Most important is the efficiency of air distribution in the pool hall. Poor arrangements are often found and reduce the efficiency of pool hall ventilation massively.
ESG can guide its customers to the optimum solution, which will reduce the energy costs by up to 80% compared to no energy conservation. The Carbon Trust report on pool hall ventilation confirmed this; our system has the lowest energy and life costs.