Anglia Renewable Energy

How Long Does it Take to Install the System?

A standard domestic installation takes 1-2 days to complete with little interference to your hot water supply. Our tradesmen will discuss each installation with you and determine the best route for pipes and wiring etc. before any work starts insuring that the install runs smoothly and works sympathetically with your home. Our products are guaranteed up to 25 years and have an expected life span of more than 25 years, adding value to your home as well as increased independence from ever rising fuel costs.

Do I need a South Facing Roof?

Most people assume that they need to have a south facing roof to install a solar hot water heating system but it is possible to fit an east–west system which means really any house can have one fitted. As long there is direct sunlight at some stage of the day and the area where the panels are fitted are not shaded from tall trees or large buildings.

How much heat will I gain?

The amount of heat you achieve from our solar water heating systems will vary according to local conditions and also with the changing seasons. In summer we get almost 10 times the amount of solar energy that we do in the winter. In the summer, you can expect to get 14kWh of heat per day from a single 20-tube panel, whereas in December you can expect only 1.15kWh per day on average. Even in the winter, it is possible to preheat the water to 40°C or more if the sun comes out. In fact, if you fit multiple panels, it is possible to heat your hot water to 100°C in January.

How hot will the water get?

This depends on the size of the cylinder you have and the amount of water you use. A smaller cylinder will be heated to higher temperatures, whereas a larger cylinder will heat more water, but not to the same extent. Systems are generally designed to heat water to approximately 65C, although during the winter it may be necessary to 'top-up' the heat on less sunny days. Large solar panel arrays, running high temperature solar antifreeze at high pressures can be designed to achieve temperatures of 170C or more!

What size are the Solar Collectors?

The collectors vary in size according to the application, the size of the property and the number of occupants we have a wide array of products to suit any application required at time of survey we will be able to discuss what best meets your individual requirements.

Will my roof need to be strengthened?

The solar panel in operation an weigh between 25-70kg. When you consider the weight of the existing tiles or slates, this is a very small amount of extra weight for the roof to hold. Generally there is no requirement to strengthen a house roof prior to mounting the solar panel, except if you are fitting a panel to a very old roof, which has sagging and decaying timbers.

Where do these Solar Panels need placing and at what angle?

Panels should be sited on a south facing wall or roof. In fact, anywhere between South-West and South East will give good results. If you are limited to an East-West facing system, then you will need two panels to provide the same amount of hot water as a single south-facing roof slope. The most frequent solution to this problem is normally to mount one panel on the east slope and a second panel on the west slope. A special controller is available for East/West facing installations. The panels should be mounted at the angle of your latitude. For example, at our location in the UK, this is 53°. This is the average optimum angle. In fact, in winter the optimum angle is 15 °steeper, whereas in the summer it is 15°; shallower. The panels will function anywhere between 15° and 90°; angle of inclination. This is actually academic, a variation of 15°; will make very little difference to the output, so most people simply settle for whatever angle their roof slope is. The extra cost of trying to stand panels off the roof to achieve better efficiency would probably be better spent on purchasing a second panel.

Are spares available?

Yes, spares are always available, should you need them. However with no moving parts, it is very unlikely that you will need to replace anything. The glass is made of borosilicate glass (otherwise known as Pyrex) so they are actually very tough.

Are the panels guaranteed?

As a company we offer a 5 year guarantee, although, with no moving parts the panels are extremely long-lived, probably in excess of 25 years. Depending on the product you choose you individual parts IE panel etc. are also guaranteed up to 25 years by the manufacturer.

How much maintenance do the systems require?

We recommend a 5 year service to any system installed to replace glycol and fluids and make sure everything is working properly other than that the systems need very little maintenance. You should occasionally check the system pressure, to make sure there has been no water loss and to check for any air in the system.

Are The Tubes Fragile? Are they tough enough to survive impact from falling hailstones, for instance?

The tubes are made from borosilicate glass, which is very tough (also known as Pyrex). The tubes are designed to withstand hailstones of up to 35mm - so they are unlikely to be broken.

What size solar cylinder should I fit?

The size of the cylinder is dependent on both the hot water requirements and the amount of occupants. Each system is designed for the panels and cylinder are designed to meet these requirements. A 150L cylinder may only require 1 panel where as a 250L would require 2 panels and so on. In each case we will discuss what the best option would be at time of survey.

What about freezing in Cold Weather?

The solar panel is very well insulated - the manifold is surrounded by 2"of Rockwool insulation. This is better than your outdoor water pipes, so it is unlikely to freeze except in exceptionally cold weather. However, as a further fail-safe, we install a DELTASOL B controller which has 'freeze protection' function. This monitors the temperature of the collector and if it falls below 4° Centigrade, it will turn on the pump, allowing water to circulate and heat the manifold. The system is also fitted with a consumer friendly Glycol to prevent freezing at much lower temperatures.

Do I need planning permission?

In most cases, no. Evacuated tube solar panels are considered in the same way as roof windows. Unless you live in a listed building, it is unlikely that it will require planning permission. Even if you do live in a listed building, you can usually fit the panel to the rear of the building, or at ground level without requiring planning permission

Can I power the pump with solar energy?

Yes, this is possible. For flat plate collectors, manufacturers will specify a 5W photovoltaic panel, and a 5-10W low voltage pump. This is because flat plate collectors do not work efficiently in low sun conditions, so the pump only needs to function in bright sunlight. This is insufficient for evacuated tubes, which due to their high efficiency will require pump circulation even in overcast conditions. For this reason, the pump should be rated at least 10W and the panel 20W to provide sufficient circulation. At the moment, there is no cost-effective low voltage pump on the market suitable for pumping hot water. The most popular 12v solar pump, the 'Ivan' retails at around £150-200, making this an expensive option. It is possible to use a solar photovoltaic panel to drive a mains inverter, powering a standard 220v circulation pump, but most customers do not want the complexity of such as system.

How many panels/tubes do I require to meet my household needs?

This is a difficult question to answer as it depends on your water usage. For example, a single person who lives in a motor home may only use 70 litres of hot water over a two week period whereas a young couple once estimated their hot water consumption to be at least 400 litres per day. First you should calculate how large a hot water cylinder you require to meet your needs. Solar cylinders are normally designed to store water for use over two days, rather than one, thus allowing you hot water even if the following day is cloudy. Once you have calculated your cylinder size, you can estimate your panel size from this which vary from which product you choose.

Can I heat my house with evacuated solar tubes?

There is 10 times more sun energy in the summer than in the winter; therefore you immediately have the problem that the bulk of the energy that's available is at the wrong time of year. The other problem with using solar to heat your house is that the energy is not present at the times when it is really cold - at night, on very overcast days, in winter evenings etc. In practice you can provide a significant amount of supplementary heat in the spring and autumn (and some people have implemented such systems), but the contribution in the winter will be minimal, restricted to sunny days, but you will need to fit many more panels as heating a house is a far bigger task than heating an insulated cylinder of water. Our advice is not to go down this route as the benefits from such a system are not practical both financially and from the return you will receive.

How much heat energy can I store in my cylinder?

Let's use this example - a 260 litre cylinder of water, heated to 65°C. Assuming that room temperature in the house is 18°C, then the difference between the cylinder water and ambient air temperature (DT) is 47°C. The heat energy stored can be calculated by multiplying together the volume of water in the tank (in litres) by the DT by the specific heat capacity of water (4200kJ/kg K) - i.e. 260 x 47 x 4200 = 51.3MJ. If we are really fussy, we can add the heat capacity of the copper cylinder itself - i.e. 0.2MJ. If we divide this by 3.6M, we arrive at the number of kWh storage i.e. 14.3kWh.

What about overheating?

Many people worry about this unnecessarily. On systems with long pipe runs, the maximum temperature will be governed by the insulation on the pipes; as the pipes get hotter, heat loss will increase (a hotter object looses heat faster than a cooler object). If you correctly specify a system, overheating is not likely to be an issue. However, if the Solar Water Cylinders are too big for the system, you will find that you need to consider cooling issues rather than overheating, particularly if you plan to go away on holiday during mid summer (i.e. no water drawn off for a week or two). There are various ways to do it, using the BS4 controller: Overheating protection can be achieved by setting the controller to continue to circulate the water after the sun goes down - this effectively utilises the pipe work to cool the cylinder. When the cylinder drops below the set temperature, it ceases to circulate. 'After cooling' function - when enabled, this function will divert the solar heated water through a separate loop to dump the excess heat.