Conditions Of Intermittent Heating Research Articles

Investigation of the Thermal Effect of Building Envelopes of Individual Building under Intermittent Heating

The article deals with the engineering technique for determining the heating time of building envelope constructions in the conditions of intermittent heating. The authors present the results of the calculation of the temperature field in the single-layer claydit outer wall, resulting from the exact solution of nonstandard heat conduction problem. To estimate the time of heating and thermal energy consumption for heating the multilayer envelope constructions, an approximate analytical method is developed, the error of which is determined by comparing with the exact solution for a single-layer wall. With the help of this method, it is conducted the analysis of dynamic property and energy consumption for heating of claydit external wall, insulated from the inside with the help of extruded polystyrene foam.

Simulation of the Mode of the Intermittent Heating for the Combined Heat Supply System Equipped with the Heat Pump

Against a background of an abrupt increase in utility prices in Ukraine a problem of the saving of energy resources and the search for energy saving technologies for heat supply systems becomes a burning issue. The heat supply systems of public buildings with the double-period operation mode, in particular working and standby conditions provoke a keen interest. This paper gives consideration to the issues of the integrated approach to the reduction of the energy consumption by the heat supply systems of the buildings. The issues related to the use of renewable heat sources for combined heat supply systems were touched upon. The factors that affect the use of thermal pumps with the heat source, in particular the open air in heat supply systems have been analyzed. A circuit diagram for combined heat supply to training buildings of the university using the thermal pump and a gas condensation boiler has been developed. Intermittent heating conditions for the public buildings were proposed. The operation modes of the heat supply system of a building using thermal pumps and the intermittent heating were simulated. The recommendations on the use of traditional and renewable heat sources in combined heat supply systems were given. The saving efficiency due to the use of intermittent heating mode for public buildings was shown.

현대 온돌 시스템 적용을 위한 신한옥 바닥난방의 열적특성 비교

The experiment on thermal characteristics of on-dol systems were carried out to apply to New Han-ok's heating system. Change of surface temperature varied with heating times, distribution of surface temperature, radiation property were surveid on four on-dol system in laboratory conditions. Followings are results. 1) "Hwang-to unit" was most favorable condition of the distribution of floor surface temperature. And the results from reaching time to thermal comfort temperature of on-dol system showed that "Hwang-to unit" was the most favorable to continuance of floor temperature. 2) There were a little difference in surface floor radiations of <TEX>$30^{\circ}C$</TEX> for three wet on dol-systems. 3) It was suggested that "Hwang-to unit" is the most appropriate to floor heating system of new han-ok considering eco-friendship and continuance of floor temperature in intermittent heating condition.

Thermal performance of phase change material energy storage floor for active solar water-heating system

The conventional active solar water-heating floor system contains a big water tank to store energy in the day time for heating at night, which takes much building space and is very heavy. In order to reduce the water tank volume or even cancel the tank, a novel structure of an integrated water pipe floor heating system using shapestabilized phase change materials (SSPCM) for thermal energy storage was developed and experimentally studied in this paper. The thermal performances of the floors with and without the SSPCM were compared under the intermittent heating condition. The results show that the Energy Storage Ratio (ESR) of the SSPCM floor is much higher than that of the non-SSPCM floor; the SSPCM floor heating system can provide stable heat flux and prevent a large attenuation of the floor surface temperature. Also, the SSPCM floor heating system dampens the indoor temperature swing by about 50% and increases the minimum indoor air temperature by 2°C–3°C under experimental conditions. The SSPCM floor heating system has a potential of making use of the daytime solar energy for heating at night efficiently.

Corrosion inhibitors for cast iron and other metals in ethylene glycol solutions and in mains water

AbstractEthylene glycol solutions containing 1.5% of sodium benzoate + 0.1% of sodium nitrite will protect cast iron only if the system is initially heated. A mixture of 5.0% sodium benzoate + 0.3% sodium nitrite in 25% ethylene glycol has been shown to be effective in preventing the corrosion of cast iron and other metals both at room temperature and in conditions of intermittent heating. The use of sodium benzoate/sodium nitrite mixtures, sodium nitrite, disodium hydrogen phosphate and potassium chromate as inhibitors for cast iron in mains water has been examined. In the absence of inhibitors the reduced rate of corrosion of many metals in ethylene glycol solutions as compared with mains water has been demonstrated and the significance of this in the maintenance of vehicle cooling systems discussed. Electrode‐potential/time curves obtained for various metals in ethylene glycol solutions have consistently reflected the corrosion behaviour of these metals in the solutions studied.

MEEHANITE HA

Abstract MEEHANITE HA is a free machining high tensile engineering material designed especially to withstand intermittent heating conditions in service. This type of Meehanite metal resists growth under alternating heating conditions at temperatures up to 1100 deg. F. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as creep. It also includes information on casting and machining. Filing Code: CI-18. Producer or source: Meehanite Metal Corporation.

Sodium benzoate and sodium nitrite as corrosion‐inhibitors in ethylene glycol anti‐freeze solutions. I. Laboratory investigations

AbstractThe addition of 1·5% sodium benzoate and 0·1% sodium nitrite to a 20% ethylene glycol anti‐freeze solution effectively prevents corrosion of cast iron and soldered joints in conditions of intermittent heating. In the absence of benzoate, sodium nitrite protects cast iron but increases the attack on soldered joints in glycol solutions, the intensity of attack increasing considerably over the range 0·1 to 1·5% sodium nitrite.A short initial period of heating is necessary to ensure complete protection of cast iron in 20% glycol solution containing 1·5% sodium benzoate + 0·1% sodium nitrite. At room temperature without initial heating, 0·3% sodium nitrite is required to protect machined cast iron in 20% glycol solution containing 1·0 or 1·5% sodium benzoate; with 30% glycol and 1·0 or 1·5% sodium benzoate, 0·1% nitrite is sufficient. With ‘as‐cast’ surfaces higher concentrations of sodium nitrite are required to prevent rusting.

Heat Requirements of Buildings

A VALUABLE compendium of information has been issued by the Institution of Heating and Ventilating Engineers in a publication entitled “Recommendations for the Computation of Heat Requirements for Buildings” (Pp. iii+41. Is. 9d.) This comprises a section of the guide to current practice which was-recently compiled for the use of members, and it places at the disposal of all interested in the subject a most comprehensive collection of data strictly in accordance with present-day practice. The information is conveniently grouped in three parts. That on temperature-rise and rates of change gives the recommended values applicable to buildings ranging alphabetically from aircraft sheds to warehouses. The design of heating and ventilating installations has been, in recent years, greatly influenced by legislation affecting factories, and a special section has been devoted to this class of building. Heat transmittance co-efficients for walls, floors and roofs in a variety of materials constitute the second part, which also includes data as to the allowances to be made for height and for conditions of intermittent heating. The third part deals with conductivity data and the calculation of overall coefficients for composite walls, floors and roofs. Included in it is a table of thermal conductivity and resistivity of practically all the proprietary materials used in building construction. Much of the information given has been obtained from such independent sources as the National Physical Laboratory and the U. S. Bureau of Standards, and for the benefit of those unfamiliar with heat-loss calculations as applied to buildings a typical example is included.