Fig1: Operation of the BITERS in a building

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1 Sunslate BITERS The BITERS (Building Integrated Thermal Electric Roofing System) is a solar hybrid system which could convert sun s energy both into thermal energy and electricity. It is totally building integrated. The Sunslate which is a BIPV product converts the solar energy into dc power and the metal batten together with the tubing installed beneath converts solar energy into thermal energy. Components and Functions: The Sunslate is a BIPV (Building Integrated Photovoltaic) roof tile with a solar module glued to the Eternit tile. The Sunslate thermal and electric system would consist of the Sunslate mounted on a metal batten which also holds the thermal tubing. Sunslate is the photovoltaic solar roof tile that converts solar energy into DC electricity. The metal batten which holds the thermal tubing that collects solar energy and converts it into thermal energy through running the liquid in the thermal tubing. Initially, we have to consider the thermal part of the system because it has to be installed first. The metal batten will be mounted horizontally across the roof onto the battens that goes vertically up the roof. Once the metal battens are installed, the thermal tubing would be mounted on the gutter of the batten horizontally across as well. The spacing between the metal battens could vary subject to the size of the Sunslate and the thermal required specification. As the metal battens are more tightly spaced, more thermal tubing could be installed which results in higher thermo energy conversion efficiency. The thermal tubing is connected to the pump and a tank with a heat exchanger. The metal batten has three applications: 1) mounts the thermal tubing, 2) transmit the heat and 3) mounts the Sunslates. The metal battens are used to mount the Sunslates. Hooks are being used to secure the mounting of the Sunslate. One hook holds down the Sunslate at the top and bottom hook supports it as it overlaps the other Sunslate. Holes are drilled in advance according to specified positions on the metal batten which will save time and also simplifies the installation procedures. The specified position would be based on the size of the Sunslate. The Sunslates would be connected in series horizontally across the roof through our custom designed j-box. The series connection of the Sunslates would form a string and the number of connections in series would be subject to the design. Each string could be connected to a miro-inverter or numerous strings could be connected in parallel on to a regular inverter or numerous Sunslates could be connected in series feeding to a regular inverter which would be subject to the size of the inverter and the system specifications. The design would depend on the specification of the system. The inverter could convert the DC electricity to AC and feed into the grid. However, if one would like to have a stand alone system, one could use the Sunslate system to charge up batteries by configuring the Sunslate at 12, 24 & 48 volt strings

2 Fig1: Operation of the BITERS in a building Operation: On the Sunslate system, once all the strings are checked and if they reached the acceptable power, they will be connected to the inverter. Then the photovoltaic system would be turned on and start supplying AC power to the grid. In the case of a standalone system, the strings could be connected to the battery via a charge controller and start storing electricity that could be used to power the dc appliances and lighting applications. Meanwhile, on the thermal system, the circulation pump could get the heat exchanger fluid to circulate through the thermal tubing and extract the heat from the roof or façade through the metal batten down to the tank with the heat exchanger where it would heat up the domestic water supply. The pump could be connected to a separate standard photovoltaic module that could meet the wattage of the pump. As the intensity of the solar power increases so would be the throughput of the liquid in the thermal tubing resulting in generating more thermal energy. In addition, while heat is being extracted through the thermal tubing from the Sunslates that is being cooled thereby prevent the degradation of efficiency in converting sunlight to DC and ultimately AC electricity. Since quite of the thermal energy had been taken out from the attic, the house

3 would be cooler which results in reduction on the air conditioning energy consumption. In case there is an excess of required energy on standard domestic hot water application, it could be stored for later use or it could be used for hot tub or heater pools which would also be subject to locations Applications: The main applications on the Sunslate hybrid system would be on slope roofs whether they are commercial or residential buildings. However, it could also be applied on curtain walls or façades on buildings. Sunlight AC DC Sunlight PV Grid Inverter Sunslate System Pump Thermal Energy heating the liquid in the tubing Domestic Hot Water storage tank with heat exchangers om Hot water to service Cold water supply Fig. 2: Block Diagram of the Sunslate BITERS system

4 Fig 3: Sunslate BITERS at the Sullivan Estate with Solar Tree in Hawaii Sullivan Estate is a holiday resort place when families rent this location for a certain period of time to enjoy their stay in Hawaii. The Sunslate system installed is quite a bit larger than is required. Since it is in a remote area and to be totally self-sustaining especially in a resort, it is always wise to have some redundancy in case anything unanticipated happens. A sizeable portion of the Sunslate system has thermal system beneath that generate thermal energy for domestic applications as well as Jacuzzis and outdoor heated pool. In addition, shown in the above photo is the Solar Tree which is being used to pump a water fountain.

5 Fig 4 Sunslate BITERS in Virginia The customer on this project put a new extension on his existing home and uses the Sunslate BITERS. It is a relatively small system which is 2.7kw and he has made substantial saving on his utility bill. Though the total size of the building is around 4,000 sq. ft and he is a heavy consumer of electricity with Jacuzzi and an outdoor swimming pool which he uses to heat them. His monthly electric bill is well over $ and the Sunslate BITERS cut his it almost half. Consequently, he has been a very happy customer after the installation. Virginia is considered as a mid-atlantic state where climate is somewhat milder then the Northeast. However, it could get down to quite cold in the winter months which would be a little below freezing. Equivalent place in Europe would be like London, Paris and Geneva. The Sunslate BITERS could be ideal in a relatively tropical or Mediterranean climate places like southern France, Italy, Greece or Florida, Bahamas & Singapore to achieve total self-sustaining. On all these locations, winters are relatively mild or do not have winter at all. In situations, when temperature goes down to below high 30 degree F, a reasonably good size storage tank would be sufficient to maintain the thermal energy throughout the winter months. One customer installed a Sunslate BITERS in northern California, throughout the last couple of years, he managed to store more than enough energy than he needed and plans to release some on other applications.

6 Fig 5. Sunslate BITERS Future House USA at the Olympic Village in Beijing, China In the case of the Future House in Beijing, since the sun hours is around 4 hours which is quite low and the climate in the winter is quite cold which would be somewhat similar to cities in Germany and northern Europe, a 7.5 kw Sunslate BITERS was installed together with a geothermal system so that it could be totally self-sustaining. Ten countries were invited by China to display their future homes at the Olympic Village prior to the Game, Future House USA was the only one that managed to achieve net zero energy status. Right Since, it is a high profile project, there is some redundancy as well in order to make sure that it would always maintain the total self-sustaining condition. Apart from the high solar energy conversion efficiency ratio, the Sunslate BITERS is aesthetically pleasing, agile in application on wide variety of roof shapes, the only BIPV roofing product that has a roof leakage warranty.