Energy efficiency is one of the most important goals of industries today. Even in our domestic life, we look to save our energy bills. Related to our post, let us take the simple example of hot water we use for bathing. We either use geysers or boil water on gas to get it hot.
These traditional methods consume more energy, either electricity or fuel. To save energy, a device called a heat pump water heater is available. It saves energy a lot and also does its primary function of heating water successfully. In this post, we will see the concept of a heat pump water heater.
Heat Pump Water Heater
As the name defines, a heat pump water heater is an electrical device which heats water through a heat pump. Rather than generating heat from electricity, this type transfers heat through heat exchange theory using natural resources. Due to this, the energy consumption is reduced to a great extent.
This heater will absorb hot air from the atmosphere and transfer it to the water to be heated. It can be termed as a reverse refrigerant cycle, which will be seen later on in the post. Because, a refrigerant will remove heat from the external environment, and this heater will instead take heat from the external environment.
A heat pump water heater comes with two main assemblies – a compressor box and a heater box. Both the components work in tandem with each other. It is to be noted that once you plan to install this heater, the first important term to check is its installation location.
Because hot air cannot be found everywhere, it must be placed outside your area in ambient temperatures or for best performance, in a furnace room. Without it, this device is of no use as there will be no hot air to intake and pass on to the water. Heaters which are installed in a hot furnace area with high temperatures provide the best result and efficiency for the water.
Heat Pump Water Heater Principle
Refer to the below image. As you can see, it consists of two main components – a compressor circuit and a heater circuit. If you want to understand it simply, then imagine this heater in place of a cooling tower in a chiller circuit. This will then be more clear to you.
The compressor circuit consists of an evaporator and a compressor. The heater circuit consists of a condenser. The cycle starts by taking hot air from the evaporator. The evaporator has an incoming low pressure and cooler refrigerant gas due to which heat exchange takes place between cold gas and hot air.
Due to this, the air becomes colder and the gas becomes relatively hotter or the pressure expands a little. This gas is then passed to the compressor, which compresses it to a high temperature and pressure gas. This high-temperature gas will be passed on to a condenser, which takes input from the water to be heated.
As the water temperature is cooler, heat exchange takes place between hot gas and cold water. Due to this, the gas becomes cooler and the water becomes warmer. Then the cycle repeats from the evaporator once again till the set temperature of the water is achieved.
If you see the whole operation, it is exactly similar to a refrigeration cycle. The only difference is that a heater replaces the cooling tower. The heater acts nothing but as a condenser only. You can then use the warm water output for your use.
The heat pump water heater assembly must be installed by experts and not any other guy in the outside area or furnace area, as the system is critical. Improper installation will not give you the desired results. Depending on how much the water is to be heated, the corresponding rating of the heater must be selected. Electricity is consumed here too, but not as much as in a geyser.
In this way, we saw the concept of a heat pump water heater.
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