The operating principle of condensing boilers is based on exploiting heat from flue gases to pre-heat cold water at the inlet of the boiler: by condensing into liquid form, flue gases recover their latent heat of vaporization, leading to 10e12% increased efficiency with respect to traditional boilers. However, monitoring the energy efficiency of condensing boilers is complex due to their nonlin...

The common phenomenon of buoyancy-induced vapor bubble lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing bubbles coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted...

The industrial production of dimethyl ether (DME) is now about 10,000 ton/year in Japan, and DME has been mainly used as an aerosol propellant. Recently, DME can be directly synthesized from water gas, carbon monoxide and hydrogen, by use of a new type catalyst dispersed in fluids. So, a large amount of DME will be supplied in future. Considering the molecular structure, the physical properties...

Anhydrous liquid ammonia has a boiling point of -33.35 C, which might suggest that it would be a difficult material to handle, particularly in light of the familiar noxious odor of the gas. However, owing to hydrogen bonding, liquid ammonia has a relatively high heat of vaporization (23.3 J/mol vs. 40.7 J/mol for H2O). Thus, if kept in an insulated vessel (e.g., a Dewar flask), its rate of vapo...

Abstract Energy crisis is a major challenge in the current world. Latent heat thermal energy storage (LHTES) systems are known as equipment with promising performance by which thermal energy can be recovered. In the present study a comprehensive theoretical and experimental investigation is performed on a LHTES system containing PEG1000 as phase change material (PCM). Discussed topics can be ca...