Passive solutions for individual comfort systems: Creating a microclimate for open plan offices

In many countries people typically spend over 90 percent of their time indoors. Therefore, the quality of the indoor environment has a big influence on the health and wellbeing of people. Standards for thermal comfort state that 80 percent of the occupants need to express satisfaction with the thermal environment to be thermally comfortable. Research from the Center of Built Environment however shows that only 11 percent of the office buildings reach this mark. The uniform indoor climate where the conventional HVAC system operates between 22°C and 24°C don’t meet the preferences of most occupants. At the same time is it very energy consuming to keep the indoor temperature between this deadband and can a lot of energy be saved widening this deadband. A possible solution can be the so called personal comfort system, where the dead band of the office is widened and the occupant can control their own thermal environment at the desk with heaters and fans. Results into these systems show an increased level of comfort and productivity. The problem is that these systems rely solely on active systems. Therefore, the research question is: How can additional passive techniques contribute to the thermal sensation of an occupant of an individual comfort system suitable for use in an open plan office spaces?As literature shows, thermal sensation and comfort is related to the heat balance of the human body. Physical aspects and the thermal regulation system of the human body influence the heat balance. At the same time there are psychological influences. The most important aspects are expectations and knowledge. These aspects were combined to create several conceptual solutions. Extended research into the use of a heat reflection screen to redirect the radiational heat loss of the human body back to the human body was done. Calculations and simulations then showed a promising result for a neck radiation screen. There are a lot of people that experience a cold thermal sensation at the neck. Placing a heat reflection screen can increase the skin temperature with approximatly 1°C. Comparing these results with the just noticeable difference which is around 0.5 °C for the neck this 1°C difference will positively influence the thermal sensation of an occupant. Different materials were researched for their emissivity and reflectivity for far infrared radiation (wavelengths that the human body emits). However, these results came out inconclusive and need extended research. The gathered information was used to design a flexible heat reflection screen for the neck that can be applied to every office chair. The original conceptual ideas where used to design an evaporation panel for cooling that can be used in combination with fans that are normally used in personal comfort systems. It is suggested to also combine biorhythmic lighting with the settings for heating and cooling; providing cool light when feeling warm and warm light when feeling cold. Architecture, Urbanism and Building Sciences | Building Technolog