Good Practice: Solar Water Heating System, Royal Orchid Sheraton Hotel, Thailand

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Setting

Country: Thailand
Location: Bangkok
Project start date: September, 2008
Project end date: March, 2009
Technology keywords: Solar Energy (heat)
Host sector: Royal Orchid Sheraton Hotel
Ref: SETatWork Good Practice #10

Objective of the Project

To save energy by reducing the use of fuel oil in boiler and use solar water heating system instead.

Flat Plate Solar Collectors (left) and Heat Pumps (right) on the roof top of Royal Orchid Sheraton Hotel

Technical Summary

Royal Orchid Sheraton hotel was opened for business about 25 years ago. It is located near by the Chaopraya river and has 740 rooms.

The hotel has 2 boilers (1 stand-by), 5 tons/hour each, to produce steam for laundry, kitchen and domestic hot water supply. Average fuel consumption (bunker oil A) of boiler was about 2,000 liter/day. There are 5 hot water generator using steam as heat source. Temperature of domestic hot water supply is about 55 °C. Average hot water consumption is about 95 m³/day at 70% occupancy.

When the price of fuel oil was increased to over 25 Baht/liter (about US$ 0.7/liter) in 2008, the hotel decided to use solar water heating system to save energy cost. At the same time, there was an incentive from the Department of Alternative Energy Development and Efficiency (DEDE) which provided hotel with a subsidy of 4,500 Baht/m² of solar collector area.

The system includes 360 m² of flat plate solar collectors, hot water storage tanks (2 x 23,000 liter), circulation pumps, and control system. The system can produce about 24,000 liter/day at an average temperature of 55 °C. The system was installed on the concrete roof top. The system operates automatically using differential thermostat. When the temperature of solar collector is about 10 degree higher than water temperature in the storage tanks, the circulation pumps are turned on, and turned off when temperature different is about 5 degree. Hot water from the storage tanks gravity flows to the existing hot water generators and discharged to the existing hot water piping system.

The hotel also installed 5 units of heat pump to produce additional hot water to meet the demand. Each unit has a capacity of 1,500-2,000L/hr.∆t 20-30°C/ Unit. The heat pump will operate only when temperature of solar heated water is below a set point, which is normally in the evening and night time. This is to ensure that there is always enough hot water supply in the storage tanks. Each heat pump can produce about 2,000 liter/hour at 50°C (at 30°C water inlet temperature). Each has a rated power consumption of 18.8 kW.

Total investment for both solar water heating system and heat pumps was about 16 million Baht. Energy saving was about 3.04 million Baht/year. Therefore, the payback period is about 5.3 years before subsidy and about 4.8 years after receiving the subsidy.

See the Good Practice Case Study PDF file for further information

Environmental and Social Benefits

(Estimate of) Greenhouse Gases abated (in metric tons of CO₂-equivalent):
Annual: 300 tCO₂/year (74,100 kg/TJ-source: 2006 IPCC Guides for National Greenhouse Gas Inventories), based on fuel oil saving of 148,516 l/year minus an increase of electricity consumption of 274 MWh/year for the heat pumps).
Up to and including 2012: 1,200 tCO₂-equivalent
Up to a period of 10 years: 3,000 tCO₂-equivalent
Up to a period of 15 years: 4,500 tCO₂-equivalent

Socio-economic aspects: The project makes use of renewable energy to produce hot water and reduce fuel oil consumption and CO₂ emission.

Economic Data

Capital Costs: Investment on solar water heating was about 6.03 million Baht (US$ 172,230) and heat pump was about 10.09 million Baht (US$ 288,290)

Financing scheme: By owner and some incentive from the Department of Alternative Energy Development and Efficiency (DEDE) which provided a subsidy of 4,500 Baht/m² (US$ 129/ m²) of solar collector area or a total of 1,607,040 Baht (US$ 45,915). (Exchange rate 35 Baht/US$)

To find similar reports, click on a keyword below:
SETatWork: Sustainable Energy Technology at Work (2008-2010) : CDM : Energy Efficiency in Buildings : Heat Generation, Recovery and Use : Heat Pumps : Solar Thermal

CEERD - Centre for Energy Environment Resource Development

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