Building integrates photovoltaics in a thermal building simulation tool

A simple approach for calculation of the electrical yield from building integrated PV (photovoltaic) systems has been implemented in BSim2002 - a program package for thermal simulation of energy and indoor climate conditions in buildings. The module – SimPv - takes advantage of the building model geometry and solar distribution routines of BSim to simulate solar irradiation on a face fitted with PV. The routines also handle shades from local and distant obstacles. The electric yield is calculated in SimPv from a very limited number of data on the PV system. Output is summarised from each individual face containing areas with PV. SimPv is intended as a simple tool to help the engineer or architect at the early stage of the building design to evaluate the potential for implementing PV in the building envelope, allowing detailed analyses of the shading problem at any time of the year. The influence from shadings can be visualised dynamically and the impact on the electrical yield calculated for any period of the year. Thus, SimPv is not a detailed PV design tool, but a decision making design phase tool. Results from simulations with SimPv have been compared with results from the PvSyst program. This paper discusses the calculation approach used in SimPv and results from an inter- model comparison exercise.