1,169,555. Lamps; cooling buildings. LITHONIA LIGHTING Inc. 19 Aug., 1966, No. 37262/66. Headings F4R and F4U. [Also in Division H1] The Specification is concerned with temperature control in illuminated air-conditioned buildings. Fig. 1 shows part of such a building. Windows 20 (described and claimed in Specification 1,169,556 absorb I.R. radiation from natural light entering the building and also cool the air immediately adjacent the windows. Heat is rejected to two water cooling systems associated with ducts 27, 28, 30, 31 running through the building. Air ducts 24 run through the cellular floors 22 to which the windows are attached. In one arrangement, fluorescent lights 21 are attached to these floor structures in a ceiling structure 68 (Fig. 2) which provides water cooling for the lamps. Any I.R. radiation generated by the lamp and/or heat otherwise accumulating near the ceiling may be removed by a grid structure 85 suspended below the ceiling and which also rejects heat to a water cooling system. Fig. 2, and Fig. 3 (not shown), depict the lamp cooling and suspension arrangement and show that the ceiling structure between lamp positions may be apertured and provided with sound absorbent material to control the acoustic properties of the room. Figs. 4-8 show details of various forms of the underhung grid structure 85. Fig. 4 depicts one cell of the rectangular grid which has fins 100 to extract heat and pass it to the bars 86 of the cooling grid through thermoelectric units 94, the leads 99 of which are insulated from the grid. The fins may be made of a material having a refractive index which varies with temperature so that the light distribution may be controlled. In Fig. 5 (not shown), the fins of Fig. 4 are replaced by an apertured heat-conductive baffle plate extending between the bridges 98 on opposite sides of the cell. In other variants the fins of Fig. 4 are replaced by a transparent sheet carrying an electroluminescent film. Structures may have two parallel transparent sheets in each cell, each sheet joining Peltier units on opposite cell walls. The sheets may bear interference films or polarizing films and the lighting characteristics of the grid may be made controllable by using in these films materials having temperature sensitive properties. Figs. 9 and 10 (not shown), disclose the arrangements for coolant supply to the grid structure and for current supply to the thermoelectric units. Figs. 11 and 12 depict luminaires housing fluorescent lamps 21. These luminaires may be hung from any convenient structure including those such as the ceiling structure 68 of Figs. 1 and 2. The lower face of the luminaire of Fig. 11 has a glass sheet 136 bearing a thermal conductor 134 and thermocouples 129 for extracting heat from air under the lower face. Heat from the thermal conductor is rejected through fins 139 in chambers 137 through which building coolant is circulated. The Peltier units are energized by further thermojunctions 142 in the luminaire facing and absorbing heat from the lamps and from lamp ballasts in the box B at the top of the luminaire-the thermojunctions 142 reject heat through fins 150 in coolant chambers 148. A variant electrical arrangement has D.C. feed in parallel with the generating thermojunctions. Another variant has D.C. feeds from a source to all units independently so that all the junctions act as Peltier coolers. The source may be a battery which also feeds inverters for producing H.F. energization of the fluorescent tubes. The lower face of the luminaire of Fig. 12 is a structure 155 similar to that of the cooling grid shown in Fig. 4. Again energizing current for the thermojunctions (not shown) on this grid is obtained by Seebeck generators 162 disposed about the fluorescent tubes. This luminaire is, for example, air-cooled. All the air leaves by the outlet 160 at the top of the luminaire but separate inlets are provided for the fins cooling the grid 155 through thermal conductors 156 (at 158), for the fins 174 cooling some of the Seebeck generators 162 (at 175), and for the fins 170 cooling the remaining Seebeck generators (at 171). The two luminaires may be modified by being provided with the lower face structure associated in the drawings with the other. In the luminaires, fins 151, 153 cool the lamp electrodes, to maintain maximum efficiency, and the lamp walls. Fig. 13 and Figs. 14-16 (not shown), depict aspects of a ceiling structure dependent from a cellular floor 240. The ceiling makes use of flat-type fluorescent lamps 213 and linking structures 221. The lower face of each lamp is bonded to a thermally conductive grid 212 and the upper face contacts a dished thermal conductor 214. Heat is extracted from the grid (room and lamp heat) and from the thermal conductor by the linking structure 221 which contains ducts 219, 220 through which coolant is fed via pipes 215, 216 from cooling towers associated with the building. Heat transfer from the thermal conductor to structure 221 is direct, but that from the grid 212 to the structure 221 takes place through Bi 2 Te 3 or PbTe thermocouples 227. (Detail in Fig. 15, not shown.) The direction of heat transfer through these thermocouples may be reversed as desired to suit changing conditions. Air may be led to the room from the cellular ceiling by ducts 241 feeding through the hollow centres of the linking structures 221 and which have outlet grids 242. It is suggested that structures like those described may be made in which the thermoelectric devices (heat pumps) are replaced by chemical heat pumps of a type similar to absorbtion cycle refrigerators.