AIVC - Air Infiltration and Ventilation Centre

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Influence of air exchange through small openings between rooms

This paper investigates, using CFD simulation, the influence on energy and comfort of the position of small openings for air exchange between rooms in ventilated and air-conditioned rooms of highly airtight houses. Measurements of velocities and temperatures were operated in a Japanese house with floor heating and central air conditioning system providing some fresh airl. Results agree with these of CFD calculations. Calculations were used to search for the optimal position of small ventilation openings between rooms.

Decoupling outdoor air and space thermal control

The article presents the advantages of decoupling the outdoor ventilation air cooling and dehumidification from the space cooling and dehumidification. These dual-path systems (one air handling unit for outdoor air with total energy recovery, another air handling unit for the recirculation air, and a single air supply delivery system) are used in all-air variable air volume system designs. They can be combined with CO2-based demand controlled ventilation, which offers superior control and cost savings.

Introduction to the concept of exergy

This report describes the characteristics of a thermodynamic concept, exergy, in association with building heating and cooling systems. It introduces the various forms of exergy and the mathematical formulations used to evaluate them. It gives an example of exergy calculation for space heating systems.

Displacement ventilation : smart way to deal with increased heat gains in the telecommunication equipment room

This paper gives information about the design of displacement ventilation systems for telecommunication equipment rooms, which need an increasing cooling load because of higher density and new generations of telecommunication systems.

Extension of a method of calculation of consumption of air conditioners

To evaluate innovations and efficiency as regards air-conditioning, it is necessary to know for how long and in which conditions the equipment functions, an indication related with the COOLING LOAD and which is their effectiveness - EER - on average (or Seasonal) known as SEER. We extended the concept of SEER to include all sources of electricity consumption, namely the secondary equipment, and we called this extended concept the SYSTEM SEER.

The potential for natural and hybrid cooling strategies to reduce cooling energy consumption in the United States

The aim of this study was to define whether energy savings and comfortable conditions are achievable along with a reduction or even suppression of the mechanical cooling systems.Three different cooling systems (mechanical standard air conditioning, hybrid cooling, mechanical ventilation cooling) were simulated for a typical US office space under 40 different US climatic data, to calculate energy consumptions.

Study on hybrid cooling system coupled with radiation panel and natural ventilation

The use of a hybrid cooling system using radiant cooling panels with wind-induced cross ventilation is described in this paper. Its performance is compared to the hybrid system using underfloor air-cooling. The radiant cooling panels system appears more energy efficient and brings more thermal comfort than the under-floor air cooling system.

Energy saving using UFAD & night cooling effect

Overnight free cooling in buildings brings potential benefits that have been known for some time. This study investigates those benefits when used in conjunction with an under floor air delivery system (UFAD). A detailed study using CFD was undertaken for a building in an airport in the UK with under floor air conditioning system and mechanical ventilation providing fresh air. Results show the energy consumption and peak cooling loads reductions when using night time cooling with outside air during the cooling season.

Analysis method of thermal and lighting environments and its application to the evaluation of office lighting

A method for analyzing the thermal and lighting radiations in offices building has been developed. It enables the simulation of complicated lighting environments composed of a combination of artificial lighting and solar radiation, in ventilated and air conditioned offices.

Real-time determination of optimal indoor-air condition for thermal comfort, air quality and efficient energy usage

This paper describes a method for the determination of optimal indoor conditions, using three parameter indexes: PMV (predicted mean vote) for thermal comfort, CO2 concentration for indoor air quality and cooling/heating load for efficient use of energy. A performance index of the HVAC system is calculating by adding square errors between actual and desired values. It is then minimized to find optimal indoor air conditions.