This paper summarises the work of the LowEx co-operation /1/. The aim was to promote rational use ofenergy by encouraging the use of low temperature heating systems and high temperature cooling systems ofbuildings. These systems can use a variety of fuels and renewable energy sources. Energy is used efficientlywhile providing a comfortable indoor climate. Exergy defines the quality of energy and is a concept fordesigning and assessing different heating and cooling systems. Application of exergy analysis into buildingshas not been common before.
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.
Actually and in the near future, due to the necessity of refrigeration, the need of thermal energy dissipation systems will be increased. One of the best element, is the cooling tower, but it has one mean inconvenient, what is the use of a fan. The use of the fan has the following misfortunes: waste of energy, noise, vibration and dissemination of Legionella, if it is present.
The performance of a passive cooling system was evaluated as part of design works for theproject of an auditorium. The passive cooling system incorporates an array of buried pipes together with a solar chimney. The natural ventilation is enhanced with the help of the solar chimney and fresh air is cooled by circulation within the buried pipes. The application of this system to the acclimatization of an auditorium was evaluated. A model was developed on this purpose, which allows foreseeing the temperature and relative humidity of the air in the auditorium.
For reliable operation of computer equipment in a data center, adequate cooling air must be supplied to the equipment. The distribution of cooling air through the perforated tiles in a raised-floor data center is governed by the fluid mechanics of the underfloor space. The pressure variation in that space is shown to be the cause of nonuniform distribution of airflow. The various factors that influence the distribution are discussed. The effect of floor height and tile open area is illustrated
When applying the radiant floor cooling system using Ondol - the Korean traditional radiant floor heating system - it is important to select a precise control method to maintain a stable room temperature and floor surface temperature and prevent surface condensation. Therefore, it is necessary to systematize various control methods and to conduct a comparative study of the respective control methods so as to be able to control the radiant floor heating and cooling system efficiently.
In Norway and Sweden's schools, hybrid or natural ventilation with ground-coupled fresh air intake ducts (or culverts) is the popular way of conditioning air.The ground-coupled ducts are normally made of concrete and easily accessible for inspection and cleaning; they can be divided into two parts: the air-intake culvert and the air-distribution culvert. Measurements show that the use of ground-coupled ducts along with a suitable airflow regulation is a guarantee that the supply air is colder than room air.
The potential of controlling techniques for an electrochromic device is investigated in a systematic way, using both experimental and theoretical tools. Concerning the theoretical part a model was developed in the TRNSYS environment and validated against experimental data. These data were collected from experiments, which were carried out in a PASSYS test cell with a movable wall. Having established a good model performance several cases of window types (such as a 4mm clear window and a low-e double glazing) and controlling strategies for the electrochromic device are simulated.
This paper describes the unsteady terminal and presents its characteristics gained fromexperiment. The experimental results showed that the fan-coil unit tested in the experimentwas able to provide fluctuating airflow and the velocity curve of supply airflow wasconsistent with the control signal very well. The spectrum of supply airflow is similar to thespectrum of natural wind if the control signal simulating natural wind provided. The supplyair temperature is changed when the airflow is changed.
The influence of uniformly distributed cooling load is investigated on the air velocity in theoccupied zone. The experiments have been carried out in a scaled test room of 6 6 2 mwith a scale factor 1:1.5. The room is equipped with nine vortex inlets. The inlets areuniformly distributed; every inlet supplies a cubical volume to remove the maximum possiblecooling load with a minimum airflow rate. The air supply rates based on floor area are set to30 m/(h m2). The cooling load generated by mannequins is uniformly distributed and variesbetween 0 and 180 W/m2.