Heat Emitter Research Articles

Criteria for the evaluation of laser solar energy converter systems

Assuming that a parabolic insolation-collection mirror-based solar pumped laser has a collector and heat emitter whose weights are proportional to their areas, and that the weight of the laser is negligible by comparison, the output power/unit weight can be expressed in terms of the efficiencies and working temperatures of the system. This ratio appears to be several times higher for an IBr laser than for one operating on C3F7I, because the solar utilization efficiency is greater for the former despite its lower working temperature.

Paper 6: Some Basic Considerations in the Practice of Heating, Ventilating and Air-Conditioning

This paper covers some of the basic considerations associated with the practice of heating, ventilating and air-conditioning in temperate climates.A diagrammatic representation of heat loss and gain for a room appears to provide a key to more accurate forecasting of fuel consumption for whole buildings.Further, the smaller the thermal capacity of the system and, therefore, the quicker the response rate, the larger is the possible scope for fuel savings.As far as space heating is concerned water systems are classified and there is reference to the more commonly used heat emitters and some of their characteristics. There is some reference to boiler power both for hot-water heating and steam generation.Ventilation is discussed in the context of terminal points; there is also a brief reference to noise attenuation in ducts and to balancing of systems.Air-conditioning is defined and the better known distribution methods are classified. Packaged water chillers are briefly examined and there are some suggestions regarding ‘mixing-units’. In addition there are some comments on cooling towers.In conclusion there is a plea for standardization and in this particular instance reference is made to specifications for mechanical services works.

Dry ice used to increasing extent for perishable shipments : C. T. Longaker. ( Railway Age, Vol. 109, No. 5.)

The necessity to drastically reduce the space-heating (SH) needs of residential buildings in Europe has prompted the emergence of building concepts based on a super-insulated building envelope, such as the passive house (PH) standard. In these envelopes, the SH distribution system can be simplified because it is theoretically not necessary anymore to place a heat emitter in each room, or in front of each window. There is lack of fundamental knowledge to support this simplification of the SH distribution system. The present contribution especially focuses on apartment buildings heated using a reduced number of radiators. It aims at comparing the balance between energy efficiency, thermal comfort and user satisfaction using simplified SH distribution. For this purpose, two flats built according to the Norwegian PH standard have been investigated using building simulations (using IDA-ICE), field measurements and occupant interviews. With a simplified distribution, one may suspect that occupants experience the thermal environment of rooms without heat emitter as too cold, typically bedrooms. On the contrary, the super-insulation and the high-efficiency heat recovery prevent significant temperature zoning to takes place between rooms. Even though the SH distribution is simplified, occupants rather complain about the bedroom temperature which is too warm if they do not open windows. Unfortunately, this way to control indoor temperature has a strong adverse influence on the space-heating needs, which is here investigated for different control strategies. Another limitation is the time needed to heat a bedroom only using internal door opening. It takes several hours to adjust to a higher set-point temperature; an aspect that can be critical if the bedroom temperature should be changed between daytime and nighttime.