Solar technology has been used to produce heat and electricity. Solar PV panels are installed on the roof of a building to produce household energy. Solar technology can be applied as a solar window for energy production and conservation. Heat and energy exchange occurs through windows of a house in different ways. Non- solar heat losses and gains in the form of conduction, convection and radiation, solar heat gains in the form of radiation, ventilation and infiltration are possible pathways of energy exchange through windows (US Department of Energy, 2007).
Rate of transfer through the windows is measured as thermal transmittance or U-factor. Low U-factor of a window denotes less heat exchange through the windows which conserves energy allowing consistent and comfortable room temperature (NHPC, n.d.). Solar heat gains through the windows in the form of radiation is measured by Solar heat gain coefficient (SHGC) and lower the value of SHGC, lesser the amount of solar heat transmitted through the window(NHPC, n.d.).
Solar window technologies have been developed to improve the energy efficiency. Building-integrated photovoltaics (BIPV) technology uses a transparent solar panel with standard mono-crystalline PV cells (Martin, 2011). BIPV solar windows have lower U-value and generated energy using PV cells (Martin, 2011). Passive solar design techniques can be applied to new homes to collect and store solar heat passively. Passive solar de-sign includes direct gain or the application of transparent south facing windows to collect heat, indirect gain or the thermal storage of collected heat between the south-facing windows and the living spaces mostly using a Trombe wall and isolated gain or sunspace similar to greenhouse (US Department of Energy, 2001).
Martin II, J. (2011) Solar PV Windows: BIPV Technology by Pythagoras Solar [Online] Available at http://www.solarchoice.net.au [Accessed on 23 October 2014].
National Home Performance Council (NHPC) Understanding Energy Efficient Windows [Online] Available at http://www.nhpci.org [Accessed on 23 October 2014].
US Department of Energy (2001) Passive Solar Design for the Home [Online] Available at http://www.nrel.gov [Accessed on 23 October 2014].
US Department of Energy (2007) Selecting Windows for Energy Efficiency [Online] Available at http://www.windows.lbl.gov [Accessed on 23 October 2014].