RESIDENTIAL HEATING
Residential hot water systems usually are small in size and supply just enough to meet the requirements of the people living there. The most common types are explained in detail here
​
INSTANTANEOUS WATER HEATERS
Instantaneous water heaters are basically divided into two broad categories. The tanked type or the tank less type. But in both these types, the energy input to storage capacity ratio is very high. In other words, these heaters require a very high input rate, compared to their storing capacity.
Now let us discuss these two types.
​
A) Tank types:
​
These types of heaters have a bit of storage capacity, but still the heating capacity is quite high. These heaters focus most on high heating rate, but have some storage in case of surge in hot water use in peak condition.
​
B) Tank less types:
​
These heaters have no storage capacity. They only contain the amount of water to ensure all coils are filled, and no more. Their heating rate is dependent on water flow rate and the set temperature point. These heaters contain a set of tubes passing through a burner, which heats the water as it passes through in one time passage. The device contains a flow check switch to ensure that the water is flowing through the device.
​
This tank is comparatively quite smaller than the storage type and hence can be installed near the point of use fixtures. These devices when applied properly can have an efficiency greater than the tank types for the same load. But using them out of cycle and for intermittent use may offset this efficiency.
​
RECIRCULATING TANK WATER HEATER :
Circulating tanks ensure hot water supply with minimal or no time loss. They contain provisions for returning the hot water to the water heater and hence keep recirculating the hot water in order to supply it at the the furthest end at the design temperature.
​
There are two types of loops available:
A) The dedicated loop:
​
In this type of piping system, a separate pipe is installed parallel to the hot water piping to all the faucets. It also contains a thermostat at the furthest end. Thus if the temperature of the hot water falls, it is looped back to the heater and replaced. Thus it results in less wastage of water annually.
B) The integrated loop:
​
In this type of looping system a special fitting is installed just below the fixture connecting both the cold and hot water inlets. A thermostat is also installed at the end of this particular loop. When the temperature falls below the set point, the pump switches on and uses cold water pipes to transfer this water back to the water heater. This without using expensive return piping we can ensure hot water at out fingertips
ELECTRIC OFF PEAK HEATERS:
These heaters work best in areas where electricity rates are significantly higher in peak hours as compared to the rest of the day. The heater contains information about the peak load and building current load, and sets itself for the time where the load is less, or the ‘off-peak’ condition.
​
The heater uses electricity at this time and stores the hot water, thus optimizing the efficiency and reducing running costs. Occasional small reheat may be needed to maintain the storage tank temperature. Sizing the tank according to peak load is very important in these water heaters.
