design

Many modern office buildings have highly glazed facades. Their energy efficiency and indoor climateis, however, being questioned. Therefore more and more of these buildings are being built with doubleskin facades, which can provide: a thermal buffer zone, energy savings, wind protection with openwindows, fire protection, aesthetics, solar preheating of ventilation air, sound protection, pollutantprotection with open windows, nocturnal cooling and a site for incorporation of PV cells.

In this paper the thermal behaviour of a direct ground cooling system located in Milano, Italy, isstudied by means of dynamic simulations performed in the TRNSYS environment. The simulationmodel consists of a reference building equipped with radiant panels connected to a vertical groundheat exchanger. Room thermostats and chilled surface condensation sensors provide system control.The ground heat exchanger size is adjusted in order to provide summer comfort conditions in thebuilding as well as sustainable operation over a long period.

Many modern office buildings have highly glazed facades. Their energy efficiency and indoor climateis, however, being questioned.

The design of ventilation performance of air-conditioning systems in residential buildings is not quite established. In this paper findings from a recent study of the ventilation performance and IAQ in a master bedroom in Singapore are presented. The need to design for ventilation provision in split system air-conditioning units is suggested by the findings.

Designing an HVAC system has different aims, the first one is to satisfy the user with a long-term functioning system in the most energy efficient way and the second is to increase the supply air flow. So the main objective of this paper is to give the fundamentals for a system design that takes into account the 3 factors. The benefit of a pressure controlled variable air volume (VAV) system is presented .

Isolation rooms for airborne infectious agents requires special measures to prevent air from transporting agents from the patient to surrounding rooms. This paper presents measurements for two different solutions that demonstrate that good results could be obtained by selecting construction principles that prevents air leakages and by control of ventilation airflows interlocked to door positions. Further it is estimated how different parameters influences on the transfer of infectious agents from the patient room to the surroundings.

Large spaces with high thermal loads and high air flow rates air conditioned by displacement flowsometimes require air supply through the raised floor. One favoured solution is to cover the perforated floor by an air permeable carpet. Successful solutions of this type of air outlets exist in many buildings in Germany since many years and work successfully. But design and installation require some knowledge which partly may have been lost in recent years. In newer buildings many difficulties appeared.

The paper describes the use of a synthesis in thermal network models. Simulation methods areusually based on an analysis when the optimal solution is found by means of iteration process. Presented method is developed in a frequency domain for models that are built as electric circuits. General description of the method with used equations is given. The application is demonstrated in a case study when a cooling power for one room in light-weight building is found. Resultant values are time dependent internal cooling load that ensures desired inside air temperature during summer day.

This paper introduces a simple method for a natural ventilation strategic design and the evaluation of ventilation effectiveness. A simplified integrated dynamic thermal and air flow model has been developed for natural ventilation building design at the early stage. This analytic method can perform parametric studies and an optimum opening design. The indices of overheating day and ventilation sufficiency have been proposed to evaluate the ventilation effectiveness. Computer program can perform dynamic simulation for the proposed design.

In this paper, practical recommendations for design and operation of HVAC systems are presented. The result of a proper maintenance will be less pollution and a better indoor environmental quality.