This environmentally friendly 4 Green Key Eco Rated hotel is reducing the carbon footprint of its 104 rooms by providing solar heated hot water. Hotel occupants enjoy the benefits of using renewable energy from the sun whenever they use hot water. Solar energy is absorbed by twelve flat plate solar hot water collectors (SHW), which are bolted onto the roof. The SHW collectors are located on the south-western facing side, which is the sunniest. During the interview, at 3:00 pm in mid-March, on a clear sunny day, the temperature outside was -4.5° C (23 F). It was cold outside, but the collectors were absorbing sunlight, and had already raised the temperature of the heat transfer fluid to 73 ° C (163 F).
The system has a 20-yr warranty, and the owner, who is financially minded, believes the system will reduce the electricity bill, and save enough money to pay for the entire installation before the warranty expires. The installer instructed the owner how to operate the system, which is very simple, and requires little to no attention, except on very hot days, when the heat transfer fluid temperature should be monitored.
The heat transfer fluid is circulated through black absorber plates inside the collectors, which are designed to absorb and transfer heat to the fluid, while also minimizing solar heat loss and reflection back into the atmosphere. During the summertime, the fluid temperature can reach 100 ° C (212 F), because the outside ambient temperature is higher, and heat loss is slower. However, during the winter of 2010-2011, the collectors were completely ineffective for 6-8 weeks because they were covered by snow. The system could have functioned i
f it were shoveled out.
The heat transfer fluid, a food-grade glycol, is commonly used for SHW collectors because it will not freeze in sub-zero conditions, and is non-toxic in low doses, in case of accident. Heat from the glycol is transferred to potable water in storage tanks when it is pumped through a heat exchanger. The system works so well that the owner thinks everybody wins, and also sees its benefit as a marketing tool. There are improvement to be made in the future, for example, such as connecting the system to the laundry room. However, the owner sees the greatest possibilities, as many do, in implementing renewable energy from square one during the design stages.
