Engineering News asked Solar Heat Exchangers managing member Dylan Tudor Jones about the upswing in demand and future possibilities.
The demand for off-grid power is end-user-based, as opposed to being industry-based, he says.
“The last solar boom was in the late 1970s and 1980s because there was an energy crisis,” says Jones.
The current increase in demand is a result of unstable supplies, such as those experienced during the winter months.
But the company is still unable to engage with developers about the need for renewable energy.
“We have been knocking on developers’ doors for ages, but they are reluctant to use solar hot-water systems because this may affect their bottom line,” says Jones.
The initial cost of solar hot-water systems is more than that of conventional heating methods.
Jones is pushing for solar heating to be an option for people buying property off plan, but the property-development industry is generally ignorant about the benefits of – and need for – solar water heating.
He adds that developers assume that solar hot-water systems are aesthetically unpleasant.
To prove the benefits of solar energy for water heating, Jones is compiling statistics from a project in the Drakensberg, at the Alpine health resort and conference village.
The data being collected comprises the volume of hot water used, the energy in kilowatt hours required to achieve a certain temperature and the solar contribution, also in kilowatt hours.
This information is compared with the kilowatt hours generated by the solar hot-water system.
Previously, Jones says, commercial installations were a calculated ‘guesstimation’, as one simply increased the number of solar panels in ratio to achieve the kilowatt hours.
“For example, if one panel provides 4 kWh and the customer needs 16 kWh we would have used four panels,” he says.
But the problem with this approach is that different geographical locations have different weather patterns and different amounts of sunshine.
The company is currently using a Canadian software program, RETScreen, to determine the design parameters and potential performance parameters.
This is checked against the projections of a French-designed program as well as an in-house program.
The actual collected information shows a variation of –5%.
In place for a year, Jones is now interpreting data from the project to prove the success of the solar-modelling process in the hospitality industry.
“Because the facility is a hotel and a conference centre, when the remote area had power outages, this caused problems for the kitchen,” Jones explains.
Some 4 000 l/d of hot water was required by the hotel, which equated to a total power requirement of 75,7 megawatt hours over 12 months. The water must be at 60