L.L. Vasiliev

Solar–gas solid sorption heat pump

Abstract Solid sorption short cycle heat pump (⩽10 kW) which uses physical adsorption and is of interest to the space and domestic application is designed and tested. This heat pump has a very short (12 min), nonintermittent, two adsorber heat recovery cycles with an active carbon fiber as a sorbent bed and ammonia as a working fluid. It has two energy sources: solar and gas flame. The system management consists only in actuating the special type valves to change the direction of the heating circuit and water valves to change the water cooling circuit.

Miniature heat-pipe thermal performance prediction tool : software development

Abstract The software for flat miniature heat-pipe parameters ( Q max , R hp , temperature field along the pipe surface, heat transfer coefficients in the evaporator and condenser zones h e , h c , etc.) prediction and numerical modeling was developed. The experimental data received for the flat miniature heat pipe (2.5–4 mm thickness, 50–250 mm length, 8–11 mm width) with a copper sintered powder wick saturated with water were compared with the data of numerical analysis and results showed that experimental verification testifies the validity of the software application.

Latent heat storage modules for preheating internal combustion engines: application to a bus petrol engine

The heat storage (HS) system for pre-heating a bus petrol engine before its ignition was mathematically modelled and experimentally investigated. The development of such devices is an extremely urgent problem especially for regions with a cold climate. HS system working on the effect of absorption and rejection of heat during the solid-liquid phase change of HS material is realised, tested and results of R&D are discussed. Numerical modelling was performed to calculate the HS mass-dimensional parameters. In the experimental part of the paper results of experiments on the pre-heating device to start a carburettor engine and analysis of data received are given. There is a good correlation between the experimental data and the results of numerical modelling of HS system functioning.

ACTIVATED CARBON AND HYDROGEN ADSORPTION STORAGE

Activated carbons were chosen as an efficient hydrogen sorption materials to design gas storage systems. Based on experimental data empirical dependences for choosing commercially available carbon hydrogen sorbents systems were proposed. To increase gas sorption capacity technology of carbon additional activation was applied. Different heat pipe devices for sorbent bed thermal control were developed for integrating in sorption storage vessels. Developed theoretical model of cylindrical AG vessel with internal finned heater (HP based) can be used for storage systems designing. The designed AGS systems and modified carbon sorbents are perspective for the hydrogen storage and for two-fuel automobile

Multisalt-Carbon Portable Resorption Heat Pump

Resorption systems are considered as an alternative to vapor compression systems in space cooling, industry and the building sector to satisfy the cooling demand without increasing the electricity consumption [1–3]. Conventional (compression, absorption) heat pumps are not able to function at the waste heat at the temperature level below 200 °C and they can’t provide the temperature lifts 100-150 °C. A large variety of chemical heat pumps exist, but a few resorption chemical heat pumps are available in the literature. Resorption heat pumps provide high storage capacity and high heat of reaction as compared to sensible heat generated by absorption. They ensure the cold and hot output (heating and cooling) simultaneously. Nowadays the sorption technology is steadily improving and the increase at sorption market is strongly related to the energy policy in different countries. Actual sorption technologies (liquid and solid sorption cycles) have different advantages and drawbacks with regard of their compactness, complexity, cost, the range of working temperature [2,4,5]. The resorption technology advantages at first are related to the nature friendly refrigerants such as water, ammonia, CO2 (no CFC, HCFC, HFC) and at second they are thermally driven and can be coupled with a low temperature waste heat, solar heat, burning fossil fuel, or biomass. The unique advantage of resorption systems related with its ability to use a significant number of couples solid-gas [5] without liquid phase and ensure the heat and cold production. The solid resorption machine demonstrated its possibility to be very effective thermal compressor capable to reach the compression ratio more than 100 in one single cycle, which is impossible to have with a single stage vapor compression mechanical device. The optimisation of the sorption technologies is related with multi cascading cycles [2]. From previous publication [5,6], it has been concluded, that chemical heat pumps and refrigerators based on reversible solid-gas resorption cycles could have interesting applications for space cooling, when a high temperature waste heat source is available and/or the exigencies of the harsh external environment necessitates thermal control of an object. The vibration free operation and the large number of solid-gas alternatives make it possible to provide cooling and heating output in the temperature range 243K-573K [6]. The goal of this work is an experimental verification of a basic possibility to advance two-effect sorption cycles using physical adsorption (active carbon fiber, or fabric “Busofit”) and chemical reactions of salts (NiCl2, MnCl2 , BaCl2) in the same machine at the same time interval [5–6] to double the high heat of chemical reaction and sensible heat of physical adsorption to provide high storage capacity, increase the COP and ensure the temperature lift more 100 °C between cold and hot output. Such device can be considered simultaneously as a refrigerator and steam generator, based on the low temperature waste heat application. Usually the heat pump performance can be characterised by the upgrading temperature, specific power production (cooling, or heating), coefficient of performance (COP), coefficient of amplification (COA) and exergetic efficiency. Actual temperature upgrade gives the temperature gain obtained from lower temperature (water) to the high level (steam), while the specific power production gives the amount of heat generated or extracted by the resorption heat pump to the amount of working substance used (“Busofit” + salts). Coefficient of performance COP is defined as the efficiency in cold production (enthalpy of resorption devided by heat supplied for regeneration), while coefficient of amplification COA represents the ratio of hot production to the quantity supplied for regeneration: COP = Qres/Qreg ; COA = (Qres + Qabs)/Qreg.

Long Horizontal Vapordynamic Thermosyphons for Renewable Energy Sources

ABSTRACT Thermosyphons of the large length are of great interest for being used as heat exchangers for recuperation of alternative energy sources and upgrading their potential with the aid of heat pumps. Some examples of vapordynamic themosyphons (VDT) application as the system of thermal control for solar collectors, in the air conditioning systems, devices combating snow drifts and icing on the active parts of the railway transport track structure, foodstuff baking ovens and roasters, driers, etc. are considered. It is concluded that VDT used for air conditioning, ground heat exchangers, and seasonal thermal storage systems connecting with solar thermal collectors have good opportunities.

Thermally Controlled Hydrogen Storage System Using Novel Carbon Materials

Successful development of sorption storage technologies for hydrogen assumes an active temperature control and special properties of the materials, capable to adsorb hydrogen in a reversible way.