| The government legislation and the pressures to | | | | its temperature to the required level compared to |
| minimise the carbon footprint of every project | | | | the copper coil. |
| means that we have to take into consideration the | | | | When it comes to transferring the heat to the |
| long term running costs and environmental impact of | | | | water, the key factor in determining speed is the |
| every aspect of the build programme. | | | | physical surface area of the coil in contact with the |
| The hot water system plays a key role in the overall | | | | water. The more surface area, the more heat that |
| energy consumption of a build whether it's for a | | | | can be transferred, the quicker the heat recovery |
| domestic project, a commercial office or indeed a | | | | process. |
| public sector building, such as a school or hospital, and | | | | When it comes to maximising the amount of surface |
| it is therefore vital that you specify the right product | | | | area available on the coil, copper is a much more |
| for both the environmental and long term financial | | | | flexible material than stainless steel. This means that |
| benefits. It's all too easy to delegate the specification | | | | you can squeeze more copper coil into a cylinder |
| of the hot water system to contractors. However | | | | than you can with a stainless steel coil. For example |
| without proper guidance some contractors may be | | | | on a solar coil, as a rule of thumb, many copper |
| focused on delivering a solution with the least capital | | | | cylinder manufacturers suggest approximately 0.3m |
| cost, to improve their profit margins on the project. | | | | square of coil per 1m square of solar panel?stainless |
| So how can you determine how efficient a hot | | | | steel units are often less than half that ratio. |
| water system is likely to be? | | | | Copper coils can also be available with a finned profile |
| The number one factor in deciding the efficiency of a | | | | which drastically increases the surface area of the |
| hot water cylinder is the time it takes to heat the | | | | coil, once again improving the time the heat transfer |
| contents. Clearly the less time it takes to heat the | | | | process required. |
| cylinder, the less energy is consumed, the less cost | | | | The combination of a far superior thermal |
| that is required - all other things being equal. | | | | conductivity, the ability to fit more copper coil into a |
| If we look at the basic process in a traditional hot | | | | cylinder than a stainless steel coil and the ability to |
| water system, the water is heated by the coil and | | | | incorporate a finned coil to further increase the |
| the speed of the heat is dependent on two areas. | | | | surface area, means that copper is a dramatically |
| Firstly how quickly the coil itself heats up - | | | | more efficient material to be used for hot water |
| determined by its thermal conductivity. And secondly, | | | | cylinders. |
| the surface area of the coil to transfer the heat to | | | | So when you are examining how you can enhance |
| the water. | | | | the environmental aspect of your next project and |
| When you compare the two main materials used in | | | | also give your client a low running cost solution, |
| coils, copper and stainless steel, we can see that | | | | remember to consider the hot water system and |
| copper's thermal conductivity is almost 30 times that | | | | ensure that you are using the best and most |
| of Stainless Steel. This means that it will take | | | | efficient material for the job. |
| significantly longer for the stainless steel coil to raise | | | | |