Experiments and theoretical modelling have been carried out to predict the performance of a solar-powered liquid desiccant cooling system for greenhouses. We have tested two components of the system in the laboratory using MgCl 2 desiccant: (i) a regenerator which was tested under a solar simulator and (ii) a desiccator which was installed in a test duct. Theoretical models have been developed for both regenerator and desiccator and gave good agreement with the experiments. The verified computer model is used to predict the performance of the whole system during the hot summer months in Mumbai, Chittagong, Muscat, Messina and Havana. Taking examples of temperate, subtropical, tropical and heat-tolerant tropical crops (lettuce, soya bean, tomato and cucumber respectively) we estimate the extensions in growing seasons enabled by the system. Compared to conventional evaporative cooling, the desiccant system lowers average daily maximum temperatures in the hot season by 5.5-7.5°C, sufficient to maintain viable growing conditions for lettuce throughout the year. In the case of tomato, cucumber and soya bean the system enables optimal cultivation through most summer months. It is concluded that the concept is technically viable and deserves testing by means of a pilot installation at an appropriate location.

No abstract

A novel Advanced Cryogenic Carbon Capture (A3C) process is being developed due to its potential to achieve high CO 2 capture efficiencies using low cost but high intensity heat transfer to deliver a much reduced energy consumption and process equipment size and cost. These characteristics, along with the absence of process chemicals, offer the potential for application across a range of sectors. This work presents a techno-economic evaluation for applications ranging from 3% to 35% CO 2 content.

We have directly measured properties of concentrated seawater brines produced through solar evaporation in salt works. They are sufficiently hygroscopic for use in desiccant cooling cycles which can cool air to 8.0-10.9 uC below ambient. This compares to only 3.8-8.7 uC with simple evaporative cooling. Desiccant cooling can extend the growing seasons of greenhouse crops thus providing an adaptive measure against climate change.

h i g h l i g h t sA prototype of 10 kW cooling hybrid refrigeration machine is described. The machine combines both adsorption and conventional systems. The ammonia blend R723 is the refrigerant for both sub-systems. The preliminary test results show a total cooling production of 6 kW. a r t i c l e i n f o t r a c tA proof of concept 10 kW cooling capacity hybrid refrigeration machine, designed and built at University of Warwick, is described in this paper. The hybrid system uses ammonia mixture R723 (40% Dimethyl ether, 60% Ammonia) which is compatible with conventional refrigeration copper alloy (Cu90Ni10) and environmentally friendly. It combines sorption (thermal) and conventional vapour compression (electrical) technology in two separate refrigerant loops. Shell and tubes adsorption generators with activated carbon -R723 pair are used as thermal compressor while a semi hermetic reciprocating compressor is used in the conventional vapour compression loop. The hybrid machine is designed as water chiller with an evaporation temperature of 5°C and condensing temperature of 40°C. The preliminary experimental tests are mainly designed to check the system operational functionality. Those preliminary results show a maximum cooling production of 6 kW with 2/3 from mechanical compression and 1/3 from thermal compression (adsorption cycle). Further additional work is yet to be carried in order to establish full and detailed performance of prototype under development.

No abstract

No abstract