Page 109 - GRIHA Manual Volume III - Introduction to National Rating System
P. 109
102 GRIHA Manual: Volume 3
2. System selection: It is dependent on the type of building, requirement of hot water, and
quality of water. Hard water often leaves salt deposits in the collector tubes, which
blocks the flow of water. In such areas where there is hard water, water softeners or heat
exchanger-type water heaters should be used. Climate of the area also affects the system
selection. In very cold regions, open-loop systems cannot be used as the water running
inside the tubes may freeze and spoil the whole system.
3. System installation: Solar hot water systems are usually installed on the roof or other shade-
free areas of buildings. A 100-litre capacity single collector will have an area of about 2 m 2
2
and will require about 3 m of surface area for installation. This area should ideally be on the
roof and should be completely shadow free.
Planning for installing solar water heating system should be done during the design
phase of the building to ensure that the structure of the building is capable of handling the
load of the solar water heating systems. In general, a solar water heater full of water weighs
1.2–1.4 kg per litre capacity of the storage tank. For example, a 50 litre hot water system
would weigh about 70 kg. The system should be strongly anchored in place, while duly
considering the maximum wind speed of the site.
In the northern hemisphere, the solar collector should face south in order to maximize
the collection of solar radiation. For maximum annual energy collection, the tilt of the solar
collector plate should be equal to that of the latitude of the area. Latitude +15 tilt provides
0
maximum collection during winters and latitude -15 tilt provides maximum collection
0
during summers.
0
Since the human body can tolerate temperature of up to 45 C, temperature above 55 C
0
will lead to skin burns. Thus, the set point of the storage water heater temperature should
0
be set at approximately 55 C (+/- 5 C).
0
4. Plumbing: In order to optimize efficiency of the solar hot water systems, the plumbing layout
of the building should be planned in advance to reduce costs and heat losses resulting
from inappropriate piping. Pipes and insulation should be of good quality so that they last
for a longer period and require less maintenance. Improper insulation and extremely long
length of piping can lead to heat losses, which can reduce the efficiency of the hot water
system by as much as 30%. Placing the solar water heaters close to the utility points reduces
heat losses and the cost of piping layout.
5. Maintenance: To ensure smooth functioning of solar water heaters, supply of water to the
system should be continuous. In case there are long periods when these heaters are not
used, non-transparent covers can be used to avoid over heating of the solar collectors. Also,
the solar water systems should be located in such a way that they are easily accessible for
cleaning and maintenance purposes.
2. System selection: It is dependent on the type of building, requirement of hot water, and
quality of water. Hard water often leaves salt deposits in the collector tubes, which
blocks the flow of water. In such areas where there is hard water, water softeners or heat
exchanger-type water heaters should be used. Climate of the area also affects the system
selection. In very cold regions, open-loop systems cannot be used as the water running
inside the tubes may freeze and spoil the whole system.
3. System installation: Solar hot water systems are usually installed on the roof or other shade-
free areas of buildings. A 100-litre capacity single collector will have an area of about 2 m 2
2
and will require about 3 m of surface area for installation. This area should ideally be on the
roof and should be completely shadow free.
Planning for installing solar water heating system should be done during the design
phase of the building to ensure that the structure of the building is capable of handling the
load of the solar water heating systems. In general, a solar water heater full of water weighs
1.2–1.4 kg per litre capacity of the storage tank. For example, a 50 litre hot water system
would weigh about 70 kg. The system should be strongly anchored in place, while duly
considering the maximum wind speed of the site.
In the northern hemisphere, the solar collector should face south in order to maximize
the collection of solar radiation. For maximum annual energy collection, the tilt of the solar
collector plate should be equal to that of the latitude of the area. Latitude +15 tilt provides
0
maximum collection during winters and latitude -15 tilt provides maximum collection
0
during summers.
0
Since the human body can tolerate temperature of up to 45 C, temperature above 55 C
0
will lead to skin burns. Thus, the set point of the storage water heater temperature should
0
be set at approximately 55 C (+/- 5 C).
0
4. Plumbing: In order to optimize efficiency of the solar hot water systems, the plumbing layout
of the building should be planned in advance to reduce costs and heat losses resulting
from inappropriate piping. Pipes and insulation should be of good quality so that they last
for a longer period and require less maintenance. Improper insulation and extremely long
length of piping can lead to heat losses, which can reduce the efficiency of the hot water
system by as much as 30%. Placing the solar water heaters close to the utility points reduces
heat losses and the cost of piping layout.
5. Maintenance: To ensure smooth functioning of solar water heaters, supply of water to the
system should be continuous. In case there are long periods when these heaters are not
used, non-transparent covers can be used to avoid over heating of the solar collectors. Also,
the solar water systems should be located in such a way that they are easily accessible for
cleaning and maintenance purposes.
