Water heating is the second most energy consuming segment in a house after space heating and cooling. There are many kinds of hot water systems available in the market and selecting a suitable hot water system depends upon the water needs of households.
The first hot water system was invented in the year 1868 by Ben Maughan in London. The initial hot water system used a gas burner to heat the cold water pipes but the absence of vent led to carbon monoxide poisoning in people. In the year 1888, Edwin Rudd, an American engineer, developed the world’s first automatic gas powered storage water tank heating system, a system which is widely used all over the world even in the modern times.
The Hot Water Systems can be divided into Two Categories. They are:
Tank or Storage Hot Water Systems
Tank hot water systems contain a heating element which heats the water present in the tank. The heating element can be powered by either gas or electricity. The temperature of the water is controlled by a thermostat. When the temperature of the heated water reaches a preset limit, the thermostat switches off the system. In the same way, when the temperature of the water inside the tank drops to a fixed temperature, the thermostat switches on the system for heating water.
Tankless Hot Water System
Tankless hot water systems do not incorporate tanks and heat water as and when required. Such systems have a high efficiency and much more convenient as compared to tank hot water systems. Condensing tankless water heaters that utilize exhaust gases to reheat cold water coming into the system again thereby enhancing the efficiency. Due to the absence of a tank, such hot water systems do not occupy much space and can be easily installed inside the cabinets of kitchens and bathrooms.
The Examples of Various Hot Water Systems have been discussed Here:
Gas Water Heaters
Gas water heaters contain a gas-powered burner which heats water present inside a storage tank. The gas water systems have a pilot flame which burns continuously and provides heat to the burner. The burner, in turn, heats the water from the bottom of the tank. Flue system can also be present in the heating system. This system enables the use of hot flue gases present outside the tank to heat the water which enhances the efficiency significantly.
Gas water heating systems without tanks heat the water by a burner when it passes through a pipe coil called heat exchanger. The burner is activated only when the hot water tap is opened. Thus, water is heated only when required and the absence of tank means that there is no heat loss from the tank.
Electric Water Heating Systems
Electric storage water heating systems consist of an insulated water tank where the water is heated by electric resistance elements. The water in the tank remains hot due to insulation against outside temperature.
Tankless or instantaneous electric water heating systems heat water according to demand. Water is heated by electricity powered heating element whenever a tap of hot water is turned on.
Solar Water Heating Systems
Solar water heating systems use solar energy to heat water. The cold water from the storage tank is passed to the solar collectors on the roof. The solar collectors absorb the heat energy from the sun which heats up the water present in them. The hot water returns back to the storage tank. Water can be heated either using electricity or gas.