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The results of indoor climate investigation in 7 schools of Tallinn are analyzed in the paper.In classrooms with natural air change carbon dioxide concentration at the end of the class isvery high, up to 1.5.3.5 times more than permitted level. With high occupation rate ingymnasiums of Tallinn the good indoor climate and permitted CO2 concentration at the end ofthe class can be provided only with the use of balanced ventilation.

This paper discusses the efficiency of induction motor drives for HVAC applications, basedon measurements made on three 4kW induction motor drives. Both converter efficiency aswell as induction motor efficiency is studied and in particular the total system efficiency isdetermined. Measurements have been performed on a 4kW induction motor fed by threedifferent types of frequency converters. Converters A and B use an open loop, constant fluxcontrol, where B has a L-C filter on its output.

This paper deals with measurements of temperature distribution of rotary heat recovery units.A special grid of thermocouples has been made to measure air temperature in equallydistributed sampling points on each side of a heat recovery wheel. Air flow rates and theamount of recirculation air (leakage) were measured using a tracer gas. The results show thatthe temperature profile is generally dependent on both the rotational speed of the wheel andthe flow rate.

The numerical and experimental analysis was carried out to study the thermal-hydrauliccharacteristics in elliptical finned-tube heat exchanger under the dry and air/water spray cooledsystem. Three kinds of major/minor axis ratios (2.5?2.8 and 3) were examined for the ellipticfinned-tube heat exchangers and the results were also compared with the corresponding circularfinned-tube having the same perimeter. The numerical results for the pressure and heat transfercoefficient at various inlet frontal velocities (1~5 m/s) are shown and compared with the availableexperimental data.

Field surveys on thermal environment were carried out at Station T which is a large station inTokyo, mainly in summer 2006. It appeared that the thermal environment in concourse isclosely related to passengers comfort. As the result of surveys, it was clarified that thermalenvironment in the concourse was not acceptable enough for passengers. At most place andtime, thermal environment in concourse was easily over 32C in SET*, upper limit ofacceptable range for passengers. In addition, thermal environment in the concourse waswidely distributed.

In the last decade, quite a few carbon-monoxide intoxications occurred in Hungary due to theinadequate operation of gas appliances with open combustion chamber, connected tochimneys. These cases emphasized the importance of faultless air supply of the appliancesand the safe removal of the incipient flue gases. This problem gave reason for the modellingof air supply, temperature and velocity distributions in the space that contains the gasappliance. For the modelling of changes caused by the variations in the inside or outsideambient conditions, numerical modelling can be used.

This paper conducts an experimental measuring of the airflow generated by a modern ceilingfan that has an electronic device to vary the instant rotation speed for simulating natural winds.The measuring results are then used to calculate the mean air velocity, standard deviations,turbulence intensity, equivalent frequency, power spectrum, and other comfort evaluationparameters. The results have shown that, by adopting the natural wind mode, even at a lowermean air velocity, a substantial comfort level can be achieved while consumes much lesselectric energy.

An air-condition system shall be designed to provide the required indoor environment underspecified condition. According CEN Report 1752 it could be distinguish three categories forindoor environment. Considering higher level of comfort there is a rising cost of HVACsystems.

Active chilled beams are an air conditioning solution for ventilation, cooling and heating. Bycareful design the solution can result in a comfortable indoor environment with a high degreeof individual control at a low operational cost. During the design process draught risks shouldbe analyzed since many factors can influence the resulting airflow pattern from chilled beams.The paper focuses on the factors affecting the thermal comfort in a room ventilated by chilledbeams. Both experimental results as well as theoretical considerations are included in theanalysis.

Radiant panels achieved a growing success in the last years as a cooling system, because theyguarantee improvement in comfort and energy saving.The aim of the present work is to propose a method to evaluate the thermal behavior ofradiant panels used for summer cooling. Experimental observations lead to notice that part ofthe radiant load hitting panels surface is directly removed by the refrigerating fluid (DirectWater Load), never becoming a room load.