How do they work?
When selling swimming pool heaters, adding a heat pump to the product line is more about becoming the client’s one-stop shop, rather than being ‘green’ (eco-friendly) or ‘cutting edge,’ as the principles upon which a heat pump operates are not based on new technology.
Consumers may not realize this, but they have probably used heat pumps all their lives. The heat pump family includes air conditioners, refrigerators, icemakers and freezers. The world’s first heat pump, a steam-powered icemaker, was invented in 1830. The first air conditioner was up and running in 1911, followed by the first air-to-water system in the 1950s. While there have been constant improvements to the technology, the customer can be assured the concept itself is well established.
By definition, a heat pump is a machine that moves heat from a low-temperature reservoir to a higher-temperature reservoir via mechanical means. It relies on the second law of thermodynamics which, in layman’s terms, means hot always goes to cold.
A heat pump uses a powerful fan to draw air through its evaporator coil, which is located on the unit’s exterior and resembles a radiator. It comprises metallic fins and small tubes that have super cold refrigerant running through them. When air is drawn through the coil and passes over the tubes, heat from the air is transferred to the refrigerant based on energy conversion between heat and mechanical work. The warmer refrigerant heads into the compressor, which in addition to moving the refrigerant throughout the system, compresses it, making the refrigerant even warmer. Finally, the warm refrigerant travels through a heat exchanger where its heat is transferred to the cooler pool water without ever coming into direct contact with the water itself.
Concerned about losing the client halfway through that explanation? Consider describing the mechanics as if it were a radio for heat. A radio receives electromagnetic waves (signals) through its antenna, then amplifies the stronger signal, which we hear through the speakers. A heat pump receives heat from ambient air via its evaporator coil, the refrigerant is made warmer as it travels through the compressor and then delivers the heat to the pool water via the heat exchanger.
Breaking down barriers
A heat pump’s fuel source is the free heat present in the outside air, as opposed to a gas heater, which uses propane or natural gas. Although a heat pump does use electricity, it is only to power the unit’s internal components, which amplifies the heat it draws in before it is transferred to the swimming pool. In comparison, a gas heater transfers a larger amount of heat energy to the pool, but does so at a loss, due to the amount of energy spent.
While the concept and reduced costs make heat pumps an attractive alternative heating method, dealers may face a barrier of disbelief from customers, as they may be skeptical that ‘free heat’ can actually be extracted from the air—especially in Canadian climates.
Although there may be less heat in the air amidst cooler temperatures, heat pumps are designed to find it. Even though Canada has a reputation for its cold weather, outside temperatures during the swimming season can get rather hot. Granted, the heat the unit will find in colder temperatures is certainly much less than if the outside temperature was 26.6 C (80 F), but most heat pumps can find heat when temperatures are as low as 7.2 C (45 F).
Keep in mind, homeowners decide to heat their swimming pools to maximize their investment by extending the swimming season; most Canadian families are not looking to swim in the dead of winter. A heat pump will simply add ‘bookends’ to a family’s swim season; it allows them to get in the pool earlier and keeps them there longer, at a lower cost than if they had purchased a gas heater.
