Sri Lanka
Description of technology
This water heater system comprises of a built in tank with capacity of 67.5 L and the upper surface of the tank acts as the collector of solar energy. The tank is insulated at the bottom and sides with 18 mm thick Polystyrene (Regiform) sheet and aluminium reflective foils are used for inner lying of the water heater box.
Collector and tank specification

Description NERDC
Collector type Flat plate
No. of collectors One
Gross area collected 0.74 m2
Total aperture area of the collector 0.61 m2
Tank size 140 mm dia. and 1092 mm long 04 Nos.
Weight With tank empty 22.5 kg , with fill water tank 90 kg
Storage tank capacity 67.5 lit.
Storage tank material Stainless steel
Insulation material 18 mm thick. polystyrene (regiform) sheet

At the NERD Centre the integrated solar water heating technology was taken several steps further to achieve a system which was not inferior in performance to the thermo-syphon counter parts. In fact, the day time temperatures recorded in the centre develop system were at least 10% higher than those recorded in thermo-syphon systems of similar capacity under test.
Specific Features
The hot water system made by NERDC consist of a solar collector and water tank integrated to one unit. The special feature of this unit is no interconnecting pipes for transporting water from the collector to the storage tank and the tank itself acts as t
Keywords (maximum 5)
Solar, radiation, tank
Status of Technology
Fully Commercialized
1) Low maintenance
2) Free source of energy used (solar)
3) Environmental friendly technology
Areas of application/Business opportunities
Domestic, Hotels, etc.
List of components used
Components to be fabricated;
- Stainless steel storage tank (gauge 18)
- Box iron ¾”x3/4” supporting frame
- B.H.P. sheet cover

Components to be attached;
- Heating element /thermostat control
- Pressure release valve set to pressure of 1.5 bar
Name of the component
Total area required (sqM)
1 sqM
Materials required for construction
S.S. Sheet (18 g. x 4”x8”) S.S. tube (3/4” dia.) S.S. rods (2” dia.) for sockets S.S. rods (3/4” dia.) for sockets S.S. welding rods Box iron (3/4”x3/4”) B.H.P. Sheet (plain) 3”x8” Regiform sheet (3/4”x3”x3”) Aluminium ang
Procedure of Installation
1. The storage tank is consisted with 04 Nos. cylindrical stainless steel pipes, which are interconnected with 1” s/s tube. The unit would normally be installed at a south facing inclination of 15” to 25” to suit the typical roof pitch ranging Sri
Maintenance requirements
The upper surface of the upper glazing has to be cleaned periodically during the dry season to wipe out dust.
Total investment
USD 400 (approximate selling price in Sri Lanka)
Name of the organization
National Engineering Research and Development Centre
Address/Zip code
IDB Industrial Estate,
Sri Lanka
0094 -11-2236307, 0094-11-2236384