Energetic optimal heating and cooling curves (for air supply)

New Dutch office buildings are built under strict energy efficient legislation and well equipped with insulation, condensing boilers, heat recovery systems, etc. Despite this, many buildings don’t perform as energy efficiently as expected. Also comfort problems occur in large numbers. The problem seems to be the frequently used conventional control strategies, most of which were developed at a time when buildings had no insulation and were equipped only with single glazing. These common used conventional strategies in the Netherlands are: supply air temperature of 20 °C in winter and 16 °C during summer. When these conventional strategies are used in modern office buildings, much energy is spoiled due to a mismatch between heating and cooling demands and supply on central and local level. In the intermediate season heat is supplied at central level in order to condition the supply air while at local level cooling is supplied to cool the room air temperature to its setpoint. This heating and cooling at the same moment is a non- desirable situation. In this paper a method is described how to determine the supply air temperature settings in order to minimise the energy spoiled due to mismatches in supply and demand. The method uses building simulation to derive the optimised temperature set points.  Application of this method will give energetic optimal heating and cooling curves. Energy savings of up to 35% can be realised without significant financial investments by devoting extra attention to the settings of the central AHU in HVAC systems without loss of comfort. In most cases the number of comfort complaints will also be reduced. The design method can be used in both new and existing buildings.
This paper presents:

1. A brief description of the method used to realise this energy saving.
2. A practical example
3. How this method is integrated in a building simulation tool.