Solar Water Heating Category

To be able to install a solar thermal water heating panel system you need a store of water in your property. I am often asked…

Can I keep my existing Hot Water Storage Cylinder/Tank?

Many companies offer customers the option of keeping their existing hot water storage tank. This reduces the cost of installation significantly. However, is this the right thing to do?

To determine whether this is a good idea we should look at why the cylinder is normally replaced. For this article I will use the word tank and cylinder interchangeably.

Normal hot water tanks only have a single heating coil that comes from a boiler. This heating coil enables the boiler to heat up the tank. A new tank is normally required so that the tank has a second heating coil. This coil can be connected to the solar panels.

Hot water rises so in a normal tank the hot water is at the top and the cold (inlet) is at the bottom. This means that it is best to position the second heating coil at the bottom of the cylinder. This enable the solar panels to heat up the coolest part of the tank. It is not uncommon for the top of the tank to be very hot but the bottom to be at the mains water inlet temperature of about 10 degrees. If configured in this way, on a cloudy day, when the panels are only at about 25 degrees they can still make a significant impact on your heating bills. This is because the 25 degree water can be used to heat the 10 degree bottom of the tank to 25 degrees. The final heating can then be done by your boiler.

Systems that utilise the existing tank normally operate in one of two ways. Take a look at the diagrams below.

Immersion Heater Solar Coil

This device screws into the hole in your cylinder usually dedicated to an immersion heater. This consists of a small pipe that is coiled. Apart from being a poor design for a heating coil (due to the restriction of the immersion hole), Sadly most immersion fittings are at the top of a water tank (usually designed to boost the top of the cylinder). So if the top of the tank is at 50 degrees the solar panels will need to be significantly higher than this before the system will operate.

This heavily compromised configuration mean that the output from the panels is enormously reduced. This reduction in performance would certainly outweigh the cost of replacing the water cylinder for the twin coil variety.

Direct Solar Water Heating

The other method of retaining the original cylinder is to pump the actual water you use through the solar panel. This type of system pumps water from the bottom of the cylinder through the solar panel and then back into the top of the cylinder. This method completely upsets the natural way in which the hot water rises to the top of the cylinder. This type of system would not operate if the top of the tank is hotter than the panel. Unless the tank is cold or the the sun is shining brightly the system will remain switched off.

These types of system give the user the sense of having a solar heating system without many of the benefits. This is no good for either the environment or your bank balance.

As a result Intelligent Energy Solutions only fit twin coil systems for this type of application. We always make sure that what we are fitting will give you highest performance and the best return.

At Intelligent Energy Solutions we aim to help our customers save money. Our new offer will help them do just that.

With every new solar panel order in the Leicestershire area, customers will receive a free energy monitor. The energy monitor has the capability of reducing household electricity costs by about 25%.

Solar Water Heating Panels typically reduce gas or oil bills. But we want all of our energy bills to be as low as they can be. This device gives our customers the opportunity to reduce their electricity bills as well.

If the promotion is successful Intelligent Energy Solutions intend on rolling out the offer nation wide.

For more information call 01509 768565 or fill out the enquiry form.

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.

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%.

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.