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Published on March 4, 2008

The weather is cold all year, but visitors to Baan Mae Kum Pong, a home-stay village on top of the mountains on the border between Chiang Mai and Lampang provinces, can still enjoy a warm shower in the freezing early morning or late at night with hot water the village produces from sunlight.

Located around 50 kilometres from the city of Chiang Mai and surrounded by high mountains, Baan Mae Kum Pong is a far-away land where basic electricity infrastructure cannot reach.

With only 20 kilowatts of electricity available from the grid for around 130 households, the electricity can power the village for general use, but when the 100-year-old community became a home-stay village at the end of 2000, it realised that there was not enough power to heat water to support the home-stay service and so sunlight was chosen as the village's alternative energy source.

Baan Mae Kum Pong is the first home-stay village in Chiang Mai province to adopt a new solar technology to heat water. Instead of using traditional firewood to boil water, the village relies on sunlight, thus avoiding the inevitable smoke from heating fires.

"To make our village appropriate for eco-tourism we had to make everything harmonise with nature. Hot water produced from sunlight therefore helps us serve our guests and preserve our environment," said the 53-year-old village head Proamintra Puangmala.

The village adopted solar technology to produce hot water three years ago. The system, developed by a research team from the Thermal System Research Unit at Chiang Mai University as a pilot programme, comprises three sets of flat-panel solar collectors to gather heat from sunlight to warm water.

"Instead of using electricity, we use solar energy to produce heat so the villagers can save electricity for use in their daily life," said the project leader Tanongkiat Kiatsiriroat.

With three sets of flat-panel solar collectors, the village's solar hot water system can heat 450 litres of water a day to 50 to 60 degrees Celsius. Tanongkiat said each set of solar collectors, which cover 2 square metres, could produce around 750 watts to 1 kilowatt of energy during six hours of sunlight.

The team designed the solar collector panel with mirrors, copper pipes and aluminium to absorb heat from the sun. When the thermal water system is on, the water is distributed to certain homes and then fresh water flows around the panel to be heated up before being distributed in turn.

With this system, Tanongkiat said the village could offer hot water produced from sunlight to 10 guests a day.

Of the 16 home-stay facilities in the village, the system can now support only two, while the remaining homes still produce hot water using gas.

The solar hot water system is part of the National Science and Technology Development Agency (NSTDA) Northern Network projects to bring technology to improve the quality of life for people in the community and help them utilise technology to become self reliant.

Tanongkiat said that the project was in an initial test run and to apply the technology to all 16 home-stays in the village would require more funding.

He estimated the cost of one solar hot water system set, which could produce 150 litres of hot water, was around Bt50,000, so it's suitable for use in home-stays, hospitals or places which require a high volume of hot water each day.

During the three-year test run, the team also found that not every location was suitable for solar technology. Even at Baan Mae Kum Pong, sunlight was still a problem.

"As the village is surrounded by high mountains, there is a limited amount of sunlight, so we cannot store heat energy for the whole day. Here, our solar collector can keep energy for a maximum of only six hours per day," he said.

However the system is a practical alternative for this remote area as using electricity to produce hot water was still impossible, he added. 

Pongpen Sutharoj

The Nation