Premises heating

Floor heating in industrial premises usually means hot-water pipes placed inside the concrete floor. (Electric coils or electric sheets are also used in non-industrial premises this is, however, not treated here.) Figure 8.60 shows a typical installation of heatpipes inside the floor. Note that the pipes are placed relatively deep down inside the concrete to help even out the surface temperature. 

The exposed area for heat transfer (A g) is then replaced on the premise that, for a set of similar gas turbines, there is a reasonably constant ratio between A g and the cross-sectional area of the main hot gas flow A g. Thus, writing A g = AA g = XWg/pgVg in Eq. (A3) gives... 

It is additionally recommended in the British Gas publication Guidance Notes on the Installation of Gas Pipework, Boosters and Compressors in Customers Premises (lM/16) that for buildings containing plant over 2 MW total heat input and being supplied with gas at pressures above 1 bar, a remotely operable valve shall be fitted in the gas supply to the building. In the case of large boiler houses, provision for remote operation of the valves shall be provided both inside and outside the building. 

Except for some defined types of accommodation, the use of fuel or electricity to heat premises above a temperature of 19°C is prohibited by the Fuel and Electricity (Heating) (Control) Order 1980. The current Order is an amendment to an earlier Regulation, which limited the temperature to a maximum of 20°C, and although 19°C is generally taken to refer to air temperature the Order does not specify this. The minimum temperature was laid down in the Factories Act 1961 and should be reached one hour after the commencement of occupation. 

Most ventilators are made of aluminum because of its good corrosion resistance and lightweight. On industrial premises they are normally left in mill finishes and allowed to oxidize. On commercial premises, a polypowder paint finish is normally specified for aesthetic reasons. To reduce energy losses during the heating... 

G. A. White I think I would take exception to the premise that methanation is a low thermal efficiency operation. If you look in some of the publications on methanation as a part of the total project, you will find that the majority of processes turn around and produce steam by burning coal or product gas or something else. So, if you define thermal efficiency by reduction in heating value, I would certainly agree with that. But if you then have to utilize, or you can utilize, this energy in the form of steam, I don t see that methanation represents a thermal loss. If in fact you don t produce steam in excess of what is required in the process, then it should be incorporated in the calculation of thermal efficiency. 

It has now been established that the single property which most critically defines a fire is the heat release, in particular its peak value which is indicative of the maximum intensity of the fire[l-3]. This introduction is required in order to understand one of the premises of the present work, viz. the usefulness of measuring rate of heat release and of combining its measurement with that of smoke. 

In this article, we suggest that a modified superheated-liquid model could explain many facts, but the basic premise of the model has never been established in clearly delineated experiments. The simple superheated-liquid model, developed for LNG and water explosions (see Section III), assumes the cold liquid is prevented from boiling on the hot liquid surface and may heat to its limit-of-superheat temperature. At this temperature, homogeneous nucleation results with significant local vaporization in a few microseconds. Such a mechanism has been rejected for molten metal-water interactions since the temperatures of most molten metals studied are above the critical point of water. In such cases, it would be expected that a steam film would encapsulate the water to... 

For an ionic solute dissociating into v ions, the temperature coefficient is 1/v times the right-hand side of Eq. (2.60). Again, it is assumed that the solubility is sufficiently low for the mean ionic activity coefficient to be effectively equal to unity and independent of the temperature. When this premise is not met, then corrections for the heat of dilution from the value of the solubility to infinite dilution must be added to Asoi //°b in Eq. (2.60). 

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