A new Dutch adaptive thermal comfort guideline

In practice, the commonly used Dutch design criterion for long-term thermal comfort inbuildings- the weighted temperature exceeding hours method- often leads to confusion.The criterion is hard to understand for non-experts, and many doubt the validity of thepresent criterion: how sure are we that meeting the requirements really means that futureoccupants will be comfortable? A project was initiated in order to formulate alternative waysto predict, evaluate and communicate thermal comfort performance of buildings.The result is a new Dutch thermal comfort guideline for both design and evaluationpurposes. Important properties of the new guideline are:- It distinguishes between buildings with a high versus a low degree of occupant control(free running versus centrally controlled): type ALPHA versus type BETA.- Limits are set in terms of maximum and minimum allowable operative indoortemperatures. These change with increasing or decreasing average outdoortemperatures, anticipating adaptation effects. The maximum allowable temperature fortype ALPHA buildings during warmer periods is substantially higher than for typeBETA buildings.- A buildings performance over time is characterized as the percentage of occupancytime that the 90, 80 and 70% acceptability lines are exceeded. Referring to CR 1752, abuilding is classified as a class A building if the 90% lines are never exceeded, as classB if the 80% lines and class C if the 70% lines are never exceeded.