What is solar water heating?
Solar water heating is a system for heating water using energy from the sun. Solar energy is collected by a panel/collector, which is then connected by pipes to a hot water storage device such as a hot water cylinder.
What are the benefits of solar water heating?
Solar water heaters can help save water heating costs by reducing the amount of gas and electricity needed to heat water. By using sunlight to heat water instead of combustible sources or fossil fuel-produced electricity, fewer pollutants are being introduced into the environment. Solar energy is not affected by the current shortage of electricity and does not stop providing hot water during load shedding.
How much of my total hot water requirements can a solar water heater provide?
A solar water heater can provide between 50% and 90% of your total hot water power requirements, depending on the climate and model of heater. When you don’t use the element you will save 100% of your hot water power requirements.
By how much will replacing a conventional geyser with a solar powered system reduce electricity consumption?
The electrical geyser uses on average between 30 – 50% percent of your household’s monthly electricity bill. Replacing your conventional geyser with a solar powered system will reduce that percentage of your electricity consumption by up to 70%.
What is Eskom’s involvement in the solar water heating programme?
In order to reduce the growing demand for electricity, Eskom is embarking on energy efficiency and alternative energy programmes that promote energy savings on a large scale in order to mitigate system constraints. Eskom is working towards a goal to meet government’s target of 10 000 gig-a-watt hours of renewable energy generation by 2013. Part of this is the financial assistance in the form of a rebate to assist hot water consumers to convert to solar.
How hot can the water get?
The ideal temperature of your geyser or tank is between 55 and 60⁰C. Most solar systems heat the water to between 55 – 65⁰C, but some can heat much higher than that. You need to be aware of over-performing systems so that you are not scalded by the hot water.
Unless otherwise required the water temperature at the point of use should be at, at least 38⁰C for domestic fixtures such as baths, basins and showers and at least 45⁰C (in order to melt fats) for sinks. The temperature is not meant to exceed 55⁰ C at any point of use.
What happens in winter or on rainy days, when there isn’t enough sunlight to heat the water?
Solar water tanks are better insulated than electrical geysers and can keep water hot for a longer period of time. This ensures that there is always a tank full of hot water (and a backup of hot water) in the early evenings/mornings – provided the tank size is correct. An electrical backup system is allowed on the programme provided it has a timer switch that ensures it does not operate during Eskom’s peak demand periods. Customers need to ensure suppliers/installers appropriately insulate all the pipes exposed to the elements to prevent freezing and heat loss.
How does the programme work?
The programme is structured around a rebate which reduces the selling price of a SABS approved or tested (limited time period) solar water heating system. The reduction in price is based primarily on the performance of the solar water heater and its associated electricity saving potential while taking into regard the prime interest rate, expected electricity increases. It also aims to bring the systems down to a 5-year payback period.
You receive a rebate directly from the facilitating auditors of the programme after submitting a completed claim form obtained from your installer. Only registered products, complying with the following criteria, qualify for the rebate:The system must have passed the South African Bureau of Standards (SABS) tests, and comply with the South African National Standards (SANS) for thermal, mechanical performance and safety requirements.
The supplier of the system must be registered with SESSA (Sustainable Energy Society of South Africa) solar water heating division – the industry’s self-regulating body.The system must be purchased from a registered supplier/retailer and installed by a registered installer. You will only be able to claim the rebate once the facilitating auditors receive a complete claim form and an accurate invoice.
The system must have a timer to optimise energy savings and regulate everyday usage. The system must be appropriate for the household and area in which it is installed, in terms of size, frost protection and water quality compatibility. It must have a comprehensive guarantee of at least 5 years on all major parts.
Do I need to install a new geyser, or can solar panels be added to the existing system?
Standard geysers are not designed to be utilised with solar collectors as they do not have sufficient inlets and their linings are often not designed to withstand the temperature experienced from solar energy. The supplier should evaluate the existing geyser and, based on your needs, the supplier can evaluate the possibilities of using the existing system.
What are the life-cycle expectation of the system and the total energy savings on it?
Each piece of equipment has a different savings profile which depends on various elements such as geographical area, water usage profile, number of users and the size of the system. However, on a 200 litre system, the SABS average is 5.67kWh per day at 16MJ input power. The expected life of the equipment can range from 5 to 15 years; most systems are guaranteed for 5 years.
