Renewable Energy News

Many people believe that solar panels can only be positioned facing south. This isn't true.

Which direction is best?

South facing at an angle of 35degrees will maximise the output from a solar panel and give all year round best performance.
If the system is to optimised for winter performance then a steeper angle of upto 75 degrees will improve performance. This is because the sun is lower in the sky during winter.

What if I don't have a south facing roof?

If your roof faces roughly south, anywhere between South West to South East at between 30-40 degree will reduce output by a maximum of 10%.

My roof faces East-West?

A 35 degree roof that faces east or west can be utilises but with a couple of system modifications. This type of roof will normally have a reduced output of about 20%, with this knowledge we can oversize the panels to compensate for this reduction in performance.

If roof space is lmited then panels can be fitted on both the east and west roofs. This needs a more sophisticaled pumping station but can have an output similar to a south facing roof without a massive increase in installation cost.

Labels: Solar-PhotoVoltaic-Electricity-Panels, Solar-Water-Heating-Panels

Many people don't know which renewable technology is right for them.

In some respects, experts like ourselves can make the decision easier but we thought it would be useful to cover a commonly asked question.

Which is best, Solar Panels or Heat pumps?

Unfortunately it isn't that simple. Solar panels and heat pumps perform different tasks. Solar (water heating) panels use the suns energy to contribute to the heating of your hot water storage cylinder. They cannot however be relied upon to deliver hot water everyday all year round.

Ground source heat pumps on the other hand, extract heat from the ground and use this heat to heat both domestic hot water and your central heating system.

So heat pumps offer a total solution that does not need a backup. They run cost effectively vs most traditional fuels and remove the need for oil tanks or a gas connection.

Solar panels cannot provide this level of reliability.

Solar panels and heat pumps can also be installed to work together. This type of system uses the solar panels to heat your domestic hot water but utilises the heat pump as a back up. This should cut the running costs of the heat pump for domestic hot water by 50-70 per cent.

Labels: Heat-Pumps, Solar-Water-Heating-Panels

Solar Water Heating Panels

Solar Water heating panels heat water for domestic and commercial use. Panels come in a variety of different shapes and sizes but one question that people have to decide is whether to have the panels mounted on the roof or in the roof.

On Roof Solar Panels

The easier way of retrofitting solar panels is to mount them on top of the existing roof covering. this means that the existing tiles remain in place and the panels sits directly on top. The panels are fixed to the roof joists via special brackets.

Roof integrated Panels (In Roof)

As an alternative to on roof panels the existing tiles can be removed and the panel can be fitted into the roof structure. This leaves the panels almost flush with the existing tiles.

When making a decision as to which is best there are a number of factors to consider. On roof solar panels are easier and quicker to fit. Hence the installation costs are less. However, on roof panels will add additional loading to the roof structure.

Roof integrated panels require the existing roof covering to be removed, this may raise questions with the condition of the felt beneath the tiles, if it is poor it will need rectifying. In roof panels also require expensive flashing sets to make the roof water tight. However, in roof panels aesthetically look better than on roof systems.

Of course if you have a house that has not yet had the roof fitted (new build or new extension) then roof integrated panels are almost certainly the way to go. You will also save some money as less tiles will need to purchased.

It is also worth mentioned evacuated tube solar collectors. This type of solar collector is made up of a number of tubes. Evacuated tubes are almost certainly fitted over the existing roof covering as they are more difficult to make water tight.

Labels: Solar-Water-Heating-Panels

Where does the energy used in our homes go?

This is a useful question when trying to determine payback on technology such as solar water heating panels.

Electricity generated by Solar PhotoVoltaic Panels is fairly simple to determine as this is metered and exported to the national grid at an agreed price. However, when looking at solar water heating panels this calculation becomes more complicated.

Solar water heating panels contribute to your gas or oil bill and it is not immediately obvious how much of your oil or gas is used to heat your hot water vs heating your home.

For this information there is a study that took place in 2005 by the ECI. See graph below.

This graph shows that the vast majority of energy used in our homes is for space heating. However it also shows that, of all the gas used, 31% of it is used to heat hot water. So if you install solar hot water panels and expect to save 50-70% of your hot water heating bill then you can determine that this is likely to reduce your gas bill by between 16 and 22%.

Labels: Solar-Water-Heating-Panels

Solar Collectors

Solar Collector is the term generally used to describe a device that converts the suns radiation into something more useful, such as heat or electricity. This article concentrates on the solar collectors designed for converting the suns energy into heat which in turn heats your domestic and commercial hot water. Also for this article we are going to ignore flat plate solar panels which you can read about in my other posts. If you are initially researching solar panels you should start by reading the earlier posts in this blog about solar water heating panels.

There are two types of solar collector commonly used in the UK.

- Direct Flow Solar Collectors
- Heat Pipe Solar Collectors

Both systems usually utilise an evacuated tube. This works in a similar way to your double glazing at home. It forms a vacuum barrier that stops heat transferring away from the collector and it stops the cold air cooling the heated liquid down. While this barrier is an effective heat insulator it allows most of the suns radiation to pass through into the absorber surface of the collector.

The difference between direct flow and heat pipe collectors comes when we look at how the heat is transfered from the collector to your hot water cylinder.

Direct Flow Solar Collector

These systems have a loop of pipe that runs through the evacuated tubes. The water that heats your cylinder comes into direct contact with the absorbing surface in each evacuated tube. As this water is heated by the sun it is pumped around the collector tubes and eventually passes through the secondary coil in your hot water cylinder. This secondary coil heats your hot water cylinder.

Heat Pipe Solar Collector

In this system the water does not pass through the evacuated tube, it runs in a manifold at the top of the panel. The evacuated tube contains a rod with a liquid that evaporates at a low temperature. As the liquid evaporates from the suns energy the heat rises to the top of the tube. The top of the pipe connects to a heat exchanger that heats the water in the manifold. The water in the manifold is then pumped through a coil in your storage tank and heats your hot water.

Direct Flow vs Heat Pipe Solar Collectors

Direct Flow is a very simple system that works in a similar fashion to a conventional flat plate collector but with the benefit of vacuum insulation. Some maintenance difficulties may arise if there is a problem with one of the tubes. Removing a single tube can be more demanding as the water pipes are running directly through the tube. However some of the new systems do allow the tube to be slid over the water pipes and removed fairly easily.
Heat pipes on the other hand can be easily disconnected from the manifold and replaced or maintained without fear of damaging water pipes. Heat pipe systems do tend to cost a little more than direct flow systems. Another disadvantage of heat pipes is that they rely on gravity to move the heat to the top of the pipe. This means that they always have to be installed at an angle and cannot be positioned flat against a flat roof. Putting aside the practical installation and maintenance issues the heat pipe collector will function better at lower levels of solar radiation. This is because the heat transfer fluid conducts heat much fast than the directly flowing water system.

For further information contact Intelligent Energy Solutions.

Labels: Solar-Water-Heating-Panels

Solar Water Heating Panels

Solar water heating panels use the sun's energy to heat hot water for your home. When the water in your roof is hotter than the water in your storage tank a pump is activated and this heat is transferred into your water tank. This type of panel does not generate electricity, click this link to read more about Solar PhotoVoltaic Electricity Panels.

There are two common types of solar collector used in the UK.
- Flat plate collectors
- Evacuated tube collectors

At Intelligent Energy Solutions we offer both types of panel depending on the customers requirements.

Flat plate vs Evacuated tube solar collectors/panels

Evacuated tube solar collectors are typically more efficient than flat plate collectors. This does not necessarily mean that evacuated tubes can produce more hot water just that the panel area can be reduced. Typically you will find that for a flat plate collector area of 4m2, evacuated tubes need approximately 3m2 for the same size hot water tank. With this in mind, the amount of hot water generated throughout the year will be very similar.

An independent study by the DTI compared a number of different types of system and the panel that produced the most hot water was of the flat plate variety.

The cost of the panels are now fairly similar, but some people believe that flat plate solar collectors are more aesthetically pleasing. However, technically the evacuated tubes should perform better than flat plate systems when the ambient temperature is low, i.e. in winter.

So in summary, where roof area is an issue evacuated tubes are the best option. Otherwise, you should consider both evacuated tubes and flat plate collectors.

Intelligent Energy Solutions are happy to fit either type of system as both work very well.

For more information call 01509 891256 or e-mail sales@iesolutions.co.uk.

Labels: Solar-Water-Heating-Panels

Labels: Solar-Water-Heating-Panels