Little Knowledge About Refrigeration

What is a coaxial heat exchanger? A coaxial heat exchanger is a kind kind of tube heat exchanger, it is usually used as condenser or evaporator  in a heat pump, marine air conditioner, swimming pool, water chiller etc. Mostly it is a water cold heat exchanger. The structure can be as round, rectangle, spiral, double helix and so on. The structure of coaxial heat exchanger The coaxial heat exchanger is designed as a "tube in tube" structure. Usually the outer tube is made of steel/copper, and the inner tube can be titanium, copper, copper-nickel depending on the requirements of working condition.  For the inner tube is has many spiral grooves on the surface, which will enlarge the connection surface and get more heat transferred. How does the heat exchange in the coaxial heat exchanger? Mostly water flow  in the inner tube and refrigeration flow between the outer & inner tube(refrigeration loop). The temperature of refrigeration and water are different

A pool heat pump uses electricity to operate and also uses the sun-warmed air which contributes to the efficiency of the unit. Heat Pump Pool Heaters use electricity and do not generate heat. As the pool pump circulates the swimming pool water, the water drawn from the pool passes through a filter and the heat pump water heater. The heat pump heater has a fan that draws in the outside air and circulates air through an outer evaporator air coil. Liquid refrigerant within the evaporator coil absorbs the heat from the outside air and transforms it into a gas. The warm gas in the coil then passes through the compressor. The compressor increases the heat, creating a very hot gas that then passes through the coaxial heat exchanger condenser. As the gas and pool water is pumped through the coaxial heat exchanger, the hot gas transfers its heat to the water.  The water is heated 3-5 degrees as it circulates through and then warmer water flows back into the pool.  The hot gas,