To put things in context, our new solar energy facilities have been funded by Advantage West Midlands and the EU as part of Birmingham Science City. Science City is a collaboration between the University of Birmingham and the University of Warwick. It is comprised of three research programmes and you can see their image tags on the slide.
The programme themes are Advanced Materials, Energy Futures and Translational Medicine. Each of these programmes covers two projects, which are split between Birmingham and Warwick. Our solar energy facilities fit within the Energy Efficiency Project, in itself a £10 million pound investment, which is part of the Energy Futures Programme.
As you have seen, the solar facilities are part of the Energy Efficiency Project and the mains aims of this project are given on this slide. These aims are quite non-specific and probably apply across all Science City projects.
The intention of the Science City initiative is to create a region of research excellence and establish the West Midlands as a hub for expertise in energy efficiency. We also need to improve the profile of the research themes and of the skills and equipment we have to offer.
The Energy Efficiency Project itself is made up of four themes, and these relate to:
Generation and transmission of electricity -here you can see new materials being developed for power electronics components that are designed for the high power requirements such as connecting wind turbines to the grid.
The second theme is combustion for power and in vehicles -here you can see an internal combustion engine that is connected to a dynamometer to measure the performance with new fuels and fuel mixtures.
On the slide you can see some of the components used in Hybrid powertrain technology and this idea may be familiar from the Toyota Prius, which combines a petrol engine with an electric motor.
Finally, we have the thermal technology and the built environment theme, which is where our solar energy work fits.
The Sustainable thermal energy and buildings theme itself has a few components and on the slide here you can see some of the facilities we have at Warwick.
This presentation will take you through some of the facilities we have for testing complete solar energy systems and the equipment available for testing individual components of solar collectors.
First of all, we have a highly instrumented outdoor test site. This allows us to conduct real-life testing of solar systems in their true operational environment.
In order to do this, we can't just measure the output of the system, we must have quite detailed information about the conditions in which it is operating. This includes weather data such as temperature and wind speed as well as accurate data on the amount of sunlight and also, importantly, where that light is coming from.
of solar collectors.
So, to start off with, we have a weather station, which can record information accurately at a high rate. For solar energy systems, the response time can be quite short, so it is essential that we record data over seconds or minutes rather than hours or days.
The weather station can record wind speed and direction, rainfall, radiation (or sunlight), pressure, humidity and temperature. These measurements are important in determining heat transfer coefficients, temperature differences and hence heat loss from solar panels.
of solar collectors.
As well as the heat loss from the panels, we also need to know exactly how much energy is falling on them. One of the other pieces of equipment we have is a sun-tracking system that measures the sunlight falling on our test site.
This device follows the sun and has four instruments that measure the radiation coming from it. The sun-tracker is fitted with 2 pyranometers, a pyrheliometer and a pyrgeometer.
The pryanometers are domed instruments that measure radiation in the visible wavelengths (ie light). One of these pyranometers measures the global radiation whilst the other is shaded from the sun and so measures the diffuse radiation that comes from the rest of the sky.
The pyrgeometer is also shaded but this instrument measures infra-red radiation and thereby allows us to calculate a temperature for the sky. This may sound odd but much of the heat loss from well the best solar thermal collectors will be through radiation and we need to know the sky temperature in order to calculate this heat loss.
The pyrheliometer looks a bit like a mini telescope or sighting instrument and this is because it has a sight. The pyrheliometer looks directly at the sun and the sight obscures the rest of the sky. It measures the beam radiation, which is the radiation that comes directly from the sun.
On the test site, we currently have quite a large array of solar thermal collectors. This array consists of 12 square metres of evacuated tube solar collectors, which you can see in this picture.
The collectors are connected to two thermal stores via a pump control station. The control unit can be programmed to deliver water at different temperatures to each thermal store and allows us to investigate the effects of changing control strategies, flow rates and so on.
We are also in the process of installing 4 photovoltaic collector systems that will be capable of generating over 5kW. The 36 square metres of collectors are being mounted on the roof of A-block and their performance will be monitored and compared in order to assess any difference in performance between the different brands of collector.
With the weather and radiation data from the instrumentation on the slides above, it should be possible to correlate each system's performance with variations in the ratio of diffuse to beam radiation and so on.
As well as the outdoor test site, we have a range of instruments and equipment for more controlled assessment of solar collector components and complete solar collector systems. Our instruments allow us to test the properties of materials to be used in the insulation, the absorber and the cover of a solar collector.
The optical characterisation equipment allows us to take measurements of the light transmitted through the cover material of a solar collector. We can also set this instrument up to measure the reflected light, which is important for the absorber of the collector.
Obviously it is important that as much light as possible is transmitted through the cover and then absorbed by the collector -so we need to know these properties.
The emissometer is a device to measure the emissivity of surfaces at near ambient temperatures -ie the emissivity of IR wavelengths. Most emissometers appear to be designed for looking at short wavelength radiation coming from very hot flames or very long wavelength radiation coming from objects in space.
The emissivity of a material is equal to its absorbtivity (at a particular wavelength). A solar collector will have a high absorbtivity of short (or visible) wavelengths but ideally a low emissivity of long (or infra-rad) wavelengths.
This device is used to find the emissivity of the absorber so that we can calculate the radiative heat loss to the sky -this is why we need to measure the sky temperature with the sun tracker on earlier slides.
So finally, this is the bit of kit that everyone seems to love, our own little bit of sunshine... the large area solar simulator (or giant hamster wheel!).
This simulator has an area of 3.2 square metres and allows us to test full collectors and even solar driven thermal systems. The collector is a class C simulator, designed for testing flat panel solar thermal collectors but it is due to be upgraded to allow us to use it for all sorts of photo-voltaic panel as well.
It is not too clear from the photo but the simulator has 128 bulbs in a plane three-quarters of the way up the wheels. The bulbs are distributed to give an even light distribution on the plane in which the collectors are mounted below. Through the middle of the wheels, between the lamps and the collector, there is what we call a cold sky that removes the excess Infra-Red radiation from the spectrum of the lamps.
We can simulate radiation levels from 700-1100 W/m2 that are required for performance assessment under standard conditions. The simulator also allows us to vary the wind speed and the angle of inclination of the collector. I am pretty certain that this is the only simulator in the UK with inclination angle adjustment and it must be one of only a few in the world!
We are currently in the process of testing a new solar thermal collector for Sertec Energy in order to determine its performance characteristics.
The facilities shown in these slides are available for use by anyone. The investment in equipment made by AWM is intended to act as seed funding to support the growth of research projects to develop local industry.
The key objective of Science City is to support development of regional businesses and to strengthen the University's capabilities.
As you have seen we have considerable potential to set up demonstrations such as with our Photo-Voltaic testing for New World Solar and also to collaborate with local industries to develop technologies such as with Sertec Energy.
Here are some contact details for the people involved in this work. Do contact us if you would like to engage with us on a project in this area.