An increasing impact of ventilation and air-conditioning to the total energy consumption of buildings has drawn attention to natural ventilation and passive cooling. The very common way of natural ventilation in residential buildings is passive stack ventilation. The passive stack ventilation relies on the stack effect created by the temperature difference between air temperature inside and outside a building.
Until the 1970’s most office buildings in central Europe were not equipped with mechanical cooling (airconditioning). Due to increasing requirements for thermal comfort and warmer summers, nowadays mechanical cooling is often applied to such buildings, ho
The indoor temperature can be controlled with different levels of accuracy depending on thebuilding and its HVAC system. The purpose of this study was to evaluate the potentialproductivity benefits of improved temperature control, and to apply the information for cost-benefit analyses of night-time ventilative cooling, which is a very energy efficient method ofreducing indoor daytime temperatures. We analysed the literature relating work performancewith temperature, and found a general decrement in work performance when temperaturesexceeded those associated with thermal neutrality.
Passive cooling strategies require strict adherence to the physical world. Ones imagination creates the flow of ideas that can blossom into a comfortable setting, but the reality of design, construction and cooperation has to be observed and accepted. Physical laws govern as natural processes follow the path of least resistance. In order for us to overcome these laws extra energy is required. That is why passive cooling designers must investigate how to create a comfortable setting by understanding how natural procedures work.
The thermal performance of a monozone building located in Lisbon is studied when night ventilation combined with radiative cooling is used in order to remove the heat from indoors. For simulating the thermal behaviour of the building, a commercial energy building software is used. The potential for radiative cooling in Lisbon, as well as the efficiency of the radiative cooling system were investigated previously. A validated numerical model is used in order to predict the temperature of the air at the outlet of the radiative system.
During the cold seasons, it is possible to use ambient air to cool down the coolants in air-conditioning or other refrigeration applications. Applying this free cooling reduces the energy costs of a refrigeration machine. This paper presents a general method for the economically optimal dimensioning of a free cooling system in which a heat exchanger of the counterflow or crossflow type is applied to the heat transfer between the ambient air and the coolant.
Natural night ventilation and an earth-to-air heat exchanger are applied in the low-energy office building ‘SD Worx’ in Kortrijk (Belgium). Temperatures measured during summer 2002 are used to discuss the operation and cooling effect of these passive cool
In the 1990's, concern about global warming has resulted in a resurgence of interest in naturally ventilated offices. The Belgian climate is particularly well adapted to apply cooling by natural ventilation. Indeed, except for a few hours a year, outdoor air temperature is lower than indoors. Lots of office buildings have no atrium or chimney to benefit from any stack ventilation. But natural ventilation can nevertheless be organized with only frontage windows either by single-sided ventilation or by cross ventilation.
From the view point of designing the energy efficient air conditioning system with maximized ventilation, the possibility of an all fresh air system was discussed using the simulation results of a model building in Tokyo. The algorithm of single duct cooling system for simulating the cooling coil of air handling unit based on the heat balance model of whole system components is also described as a base for the simulation of cooling effect of ventilation fresh air.
At the new institute building of Fraunhofer ISE, both mechanical and free night ventilation is used for passive cooling of the offices. The results from a monitoring of room temperatures in 21 office rooms during summer 2002 show that room temperatures exceeds 25 C in less than 8 % of the working hours, even at high ambient air temperatures. In two offices, experiments were carried out in order to determine the efficiency of night ventilation dependent on air change rate, solar and internal heat gains. During the experiments, meteorological data, air change rates, air temperatures (incl.
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