Reasons for decreased efficiency
A commercial pool service company should use the factors causing decreased efficiency in older heating systems as the main selling points as to why an aquatic facility should upgrade its heating system. Should the client ask why their current heater is not as efficient as it was when it was originally installed, the following causes of decreased efficiency can be explained.
Build up on heat exchanger tubes
Heat exchanger tubes build up with chemical residuals and calcium, which causes the unit to lower its water flow. When flow is reduced, the heater loses its ability to heat the water, thus making it less efficient than originally designed. This also results in increased energy consumption, as the heater uses more energy to heat the same amount of water in the pool.
Reduced water flow
If water flow is too fast, it creates condensation; if it is too slow, the heater is not warming the water efficiently. Further, a pump that is not working properly can also contribute to heater inefficiency due to irregular water flow. This might be an opportunity to upsell a variable frequency drive (VFD) pump to ensure the water flow through the heater remains consistent.
Condensation
Propane and natural gas, when burned, produce water as a byproduct. If the heat exchanger is too ‘cool’ the humid flue gases will condense on the fins of the heater. Condensation also causes carbon (C) to adhere to the heat exchanger. The condensate collects then drops onto the burners. The combustion is then compromised as ‘raining’ condensate that interferes with the flame pattern. This poor combustion turns into ‘soot,’ which collects on the fins and impedes the flue gasses. Not only will the condensation cause inefficiencies in the heater functionality, it will also cause oxidation on copper (Cu) from low return water temperatures.
Low gas pressure
Low gas pressure can cause damage to the internal parts of the heater causing build up that leads to heat exchanger blockage.
Lack of proper ventilation
Inadequate ventilation can cause ‘sooting,’ which prevents the heater from operating at its maximum efficiency rating. The soot layer acts like an insulator on the heat exchanger, which lessens the amount of heat transferred to the pool water.
Costs of reduced efficiency
The following examples will help in understanding the affects a heater with reduced efficiency has on a facility’s operating costs. It is important to note that one Btu will raise 0.45 kg (1 lb) of water by one degree.
