A new design guideline for the heating and cooling curve in AHU units of HVAC systems

Abstract

New Dutch office buildings are built under strict energy efficient legislation and are well equipped with insulation, condensing boilers, heat recovery systems, and so on. Despite this, many buildings do not have good energy efficiency and also do not meet comfort requirements. This has led to a large number of complaints. The problem seems to be that ‘common’ energy control strategies (heating/ cooling curves) are often used, most of the curves were based on buildings with low levels of building shell heating resistance, no additional insulation and single glazing. When these control strategies are used in modern office buildings, too much energy is used due to a mismatch between heating and cooling demands. Energy savings of up to 35% can be realized without significant financial investments by devoting extra attention to the settings of the heating/ cooling curve in the central air handling units (AHUs) of HVAC systems without loss of comfort. In most cases the number of complaints will also be reduced. The design method can be used in both new and existing buildings. The first part of this paper presents a brief description of the method used to realize this energy saving. The brief description is followed with a practical example of this method. The intention is that the approach will generate a building-specific heating/cooling curve based on an energetic optimum between the demand for heating and cooling in the zones. The input data used to generate the function cover the characteristics of the building, the organization, and the HVAC equipment.