Get to Know the Heat Pump Water Heater – Heat pump is commonly used for heating air or water. This time let’s talk about Heat Pump Water Heater.
As many of you know, we have bunch of options regarding water heating methods. There are Electric Water Heater, Solar Water Heater, Air Conditioning Water Heater, Gas Water Heater and finally, Heat Pump Water Heater.
Heat pump water heater use electricity to move heat from one place to another instead of generating heat directly. Therefore, they can be two to three times more energy efficient than conventional electric resistance water heaters.
Heat pump water heater works similar torefrigerator system, only in reverse.While a refrigerator pulls heat from inside a box and sends it into the surrounding room, a heat pump water heater pulls heat from the surrounding air and transfers it at a higher temperature to heat water in a storage tank.
The first step in the process is bringing the ambient air into the unit. A fan is hooked up to a compressor within the water heater. The heat pump is the top area of the unit that houses the compressor, evaporator coils, and expansion valve.
The ambient air from outside of the unit is brought into the unit. It’s important to note that the air doesn’t have to be “hot” as we think of it. Heat pumps are extremely efficient at absorbing heat energy from air, even at temperatures as low as 5 degrees Celsius.
The air comes into the unit and flows through the compressor and evaporator coils. The heat energy from the air is absorbed into evaporator coils. The now cooler and less humid air is expelled out the other side.
An added benefit of heat pump water heater is they produce cool, dry air. This can help keep the area of the home where the heat pump water heater is installed cool and dry.
Refrigerant is pumped through the evaporator coils. Actually, this is going on at the same time that the air is being pulled into the unit. But now we’re focusing on the compressor itself. Because refrigerant has a low boiling point (which means it will boil at cooler temperatures than water will), the heat from the air being pushed through the system brings the refrigerant to a boil. This is the first heat transfer of the process, which is from the air to the refrigerant.
This boiling refrigerant then transforms into a gas. When gas is compressed, its overall temperature increases. To make this happen, the compressor then puts added pressure onto the gas. As a result of this, the gas continues to increase in temperature.
Now we will do another heat transfer. The first heat transfer was from the air to the refrigerant. Our second will be from the refrigerant to the water itself. The heated refrigerant is housed in the condenser coils. Water comes in near the bottom of the unit, and then pumped to the top of the unit where the heat is transferred from the refrigerant in the condenser coils to the water.
The water temperature is then checked and moderated. If the water is not hot enough, then electricity will be used to heat it the rest of the way. For those who live in very hot areas, the heat from the air itself combined with the already naturally warmer water means that very minimal electricity will need to be used.
Heat pump water heaters requires installation in locations that remains in the 4.4° to 32.2°Crange year-round and provide at least 28.3 cubic meters of air space around the water heater. Air passing over the evaporator can be exhausted to the room or outdoors.
Heat pump water heaters will not operate efficiently in a cold space since they tend to cool the space they are in. Installing them in a space with excess heat, will increase their efficiency.
Like conventional models, heat pump water heater need routine maintenance. Their tanks should be flushed once a year and the anodes (heating elements) checked for corrosion. Many heat pump water heater have an air filter, too, which should be cleaned or replaced annually.
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So far, so good. So why doesn’t every house have one?
One problem with heat pump water heater is their initial cost. You can buy a traditional 50-gallon electric water heater for around $500, whereas a 50-gallon heat pump water heater might cost $1,500 or more BUT, You’ll also save money because the appliance will pay for itself in energy savings over a relatively short period of time.
According to energystar.gov, the annual average cost to operate a 50-gallon conventional electric water heater is $436. The annual average cost to operate a 50-gallon heat pump water heater is $122, so in three years the typical household will have saved nearly $1,000 in electric bills.
How it is possible to save nearly $1,000 in electric bills?
Heat pump water heaters work so efficiently because the use of electricity is minimal, it runs lower-voltage fans and compressors, it uses about a third of the electricity than that of a traditional electric water heater.
Some electricity is used in pumping refrigerant and water through the unit, but not much. If the water needs further heating after going through the heat transfer process, then backup electricity will be used to bring the water up to the desired temperature.
In a normal electric water heater, electricity is used for the entire process. In fact, heat pump water heaters are 3times more efficient than electric water heaters and 7 times more efficient than gas. Most, if not all, heat pump water heater are given Energy Star ratings for their energy efficiency.
For you who lives in minimalistic style house, heat pump water heater should be ideal as it is not taking up space on the roof like solar water heater.
To the environment, it is certainly environmentally and family friendly. Since they don’t generate heat, gas leaks and toxic emissions are non-existent from heat pump water heaters. Plus, the unit itself doesn’t get too hot outside, making it a safer option for families with pets or kids.