Load Calculation for Energy Efficient Design

Team Catalyst uses the EnergyPlus simulation engine, developed by USDOE, which incorporates the most current ASHRAE Heat Balance load calculation procedure to determine correct peak cooling loads. Recent improvements in facade glazing, lighting and computer technology mean that modern buildings have drastically reduced sensible heat loads.  However, latent loads have increased due to additional fresh air requirements mandated by green building rating systems.  Considering all these factors, we use our practical experience, and our technical expertise to develop HVAC specifications that deliver systems which run in an energy efficient and stable manner.  Stable operation has positive implications for tenant comfort.  Our designs differentiate between redundancy and oversizing and have proven outcomes in reducing base building energy bills by more than 45%!

The Heat Balance method (Peterson et al 1997) is the latest method of load calculation and energy simulation developed by ASHRAE (the American Society of Heating, Refrigeration and Air-conditioning Engineers).  It explicitly formulates inside and outside surface and zone air heat balances and simultaneously solves the resulting equations.  It is the first ASHRAE method to rely completely on computerised implementation, and also marks the change from load calculations based on energy analysis methods to those based on design day cooling load calculations.

While working with Arup, PC Thomas (Director, Team Catalyst) and Steve Moller (formerly CSIRO) produced the publication “HVAC System Size – Getting it Right”, ISBN 978-0-9803503-8-8.  It is available online at http://www.construction-innovation.info/images/HVAC_system_size.pdf.  The report concludes that HVAC systems in large commercial buildings have the risk of being significantly oversized with resultant underutilised assets and financial capital.