The International Journal of Ventilation
Click Here for information and access details to all papers published in the IJV

PHP THERMAL ANALYSIS (Revision 1 Edition) Transient Thermal Model for Calculating Indoor Temperature and Building Heat Transfer Written by Martin W Liddament Simulation Type (note the building must be thermally charged before undertaking a transient simulation)   charging   transient Building Volume (m3) Facade Area (excluding windows) (m2) Window (glazed) Area (m2) Envelope Ceiling Area (m2) Envelope (Ground) Floor Area (m2) Wall U-Value (W/m2) Glazing U-Value (W/m2) Floor U-Value (W/m2) Ceiling U-Value (W/m2) Ground Temp (C) Area of Exposed Thermal Mass (m2) Parameters temporarily fixed in beta version Thickness of thermal mass = 0.1 m Density of thermal mass = 2300 kg/m2 Specific heat of thermal mass = 650 J/kg/K Heat Transfer Coeff of mass = 3 W/m2.K Density of air = 1.26 Kg/m2 Specific heat of air = 1012 J/kg/K Solar delay = 1 hour Charging iterations = 100 Days Calculation timestep = 120 Seconds Transient simulation period = 1 day

Instructions: - Enter data as indicated. The first set of data should represent typical or normal conditions. - Click send to perform a charging operation. The building is brought to near steady state by performing 100 iterations. - Adjust input parameters as desired (thermal mass, ventilation etc to optimise normal conditions). - Repeat steady state (charging) simulation as many times as necessary for optimisation. - switch to transient simulation. - adjust temperature and solar gain data to represent an extreme heating or cooling event. - each click of the send button advances the transient simulation by 1 day. - click as often as required - data can also be changed each day if you need to incorporate a daily weather sequence. - DO NOT end a session until your task is complete since your data is not stored. - BETA Version some parameters are temporarily fixed (thermal and air parameters, solar delay, iteration time step and steady state iteration count) Technical basis - Energy balance: heat in = heat out - Solar energy retained for one hour (to be revised in later version). - Indoor heat gains: people, electrical loads, heating and cooling (negative for mechanical cooling). - Ventilation heatflow: in or out of building. - Indoor air to thermal mass transfer (heat transfer coefficient currently fixed at 3 W/m2.K). - Fabric heat exchange to outside by U value (heat inflow and outflow). Tutorial to follow USE IS AT OWN RISK Transient Thermal Model for Buildings Data Input and Results Time Outdoor Indoor Solar Vent hours Temp Heat Gain Rate Gain DO NOT ENTER DATA (Deg C) (W) (W) (L/s) HERE 01                                                             02                                                             03                                                             04                                                             05                                                             06                                                             07                                                             08                                                             09                                                             10                                                             11                                                             12                                                             13                                                             14                                                             15                                                             16                                                             17                                                             18                                                             19                                                             20                                                             21                                                             22                                                             23                                                             24