Design and Construction for Hydroxides Based Air Conditioning System with Solar Collectors for Confined Roofs

In this chapter, the methodology to determinate heat load is revised and presented. The main parameters must be fixed as function of climatization, internal thermic conditions (comfort, temperature, and humid) and the activities. According with literature, the roof structural requirements were checked. These are an important parameter because it represents the limits to the system such as load by devices (weight of equipment), orientation in solar systems (operating conditions), and building materials. The method of calculation of solar available is shown; the aim is to achieve the major collection of solar energy. Finally, the plate heat exchangers can be fabricated in gasketed, welded or module welded design characterized by the model in which the flow channels for the two heat exchanging media are sealed. The kind of exchanger is suitable depending on your requirements. The thermodynamic method of calculation of sizing the exchangers is reviewed. The aim of this section is to find the suitable devices for the operation of air-conditioning absorption system based on hydroxide

Role of Membrane Technology in Absorption Heat Pumps: A Comprehensive Review

The role of heat pumps is linked to the actions of human life. Even though the existing technologies perform well in general, they have still some problems, such as cost, installation area, components size, number of components, noise, etc. To address these issues, membrane technologies have been introduced in both heat and cooling devices. The present work proposes and studied the review of the role of membrane technology in the heat pumps. The study focuses on the advancement and replacement of membrane in the place of absorption and compression heat pump components. The detailed analysis and improvements are focused on the absorber, desorber, and heat and mass exchanger. The parameters conditions and operation of membrane technologies are given in detail. In addition to this, the innovation in the heat pumps using the membrane technology is given in detail

Experimental Performance of a Membrane Desorber with a H2O/LiCl Mixture for Absorption Chiller Applications

For absorption cooling cycles using water as a refrigerant, H2O/LiCl mixtures are suitable for replacing conventional H2O/LiBr mixtures. In addition, membrane devices can be used to develop compact and lighter absorption systems, and they can operate with H2O/LiCl mixtures. The present paper describes an experimental evaluation of a membrane desorber/condenser operating at atmospheric pressure. Two operation modes were analyzed: continuous cycle operation and intermittent operation. For the first operation mode, the maximum desorption rate was 3.49 kg/h·m2, with a solution temperature of 90.3 °C and a condensation temperature of 25.1 °C. The lowest desorption rate value was 0.26 kg/h·m2, with a solution temperature of 75.4 °C and a condensation temperature of 40.1 °C. In the second mode, after three operating hours, the refrigerant fluid produced, per 1 m2 of membrane area, 7.7, 5.6, 4.3, and 2.2 kg, at solution temperatures of 90.3, 85.3, 80.4, and 75.4 °C, respectively. A one-dimension heat and mass transfer model is presented. The calculated values of desorption rate and outlet temperatures were compared with the experimental data; a square correlation coefficient of 0.9929 was reached for the desorption rate; meanwhile, for the outlet solution temperatures and the outlet cooling-water temperatures, a square correlation coefficient up to 0.9991 was achieved. The membrane desorber has the advantages of operating at atmospheric-pressure conditions, high condensation temperature, the ability to use different saline solution working mixtures, and different operation methods. These advantages can lead to new absorption systems

Review of solar-thermal collectors powered autoclave for the sterilization of medical equipment

This literature review was based on articles published on different types of solar autoclaves used to sterilize the medical instruments. The present paper analysis the various types of solar thermal technologies and the materials used for manufacture. The operating conditions (temperature and pressure) of steam sterilizer used, the climatic conditions as well as the health center where the prototype was tested and installed were also investigated. It emerged from the revised articles that steam sterilizers are part of the systems in which solar thermal energy was used since the 1970s. Conventional solar thermal technologies were the first to be used in solar autoclave prototypes. Due to the high cost of these collectors, several researchers have invested in the design of new prototypes both solar collectors and sterilizers, based on less expensive materials. It has also observed that solar autoclave can hold a pressure steam of 0.10 MPa keeping the internal temperature at 121–140 °C for about 15–20 min

Hybrid Solar-Geothermal Energy Absorption Air-Conditioning System Operating with NaOH-H2O—Las Tres Vírgenes (Baja California Sur), “La Reforma” Case

Solar and geothermal energies are considered cleaner and more useful energy sources that can be used to avoid the negative environmental impacts caused by burning fossil fuels. Several works have reported air-conditioning systems that use solar energy coupled to geothermal renewable energy as a thermal source. In this study, an Absorption Air-Conditioning System (AACS) used sodium hydroxide-water (NaOH-H2O) instead of lithium bromide-water to reduce the cost. Low enthalpy geothermal heat was derived from two shallow wells, 50 and 55 m deep. These wells are of interest due to the thermal recovery (temperature vs. time) of 56.2 °C that was possible at the maximum depth, which can be used for the first stage of the process. These wells were coupled with solar energy as a geothermal energy application for direct uses such as air-conditioning systems. We studied the performance of an absorption cooling system operating with a NaOH-H2O mixture and using a parabolic trough plant coupled with a low enthalpy geothermal heat system as a hybrid heat source, as an alternative process that can help reduce operating costs and carbon dioxide emissions. The numerical heat transfer results showed the maximum convective heat transfer coefficient, as function of fluid velocity, and maximum temperature for a depth higher than 40 m. The results showed that the highest temperatures occur at low fluid velocities of less than or equal to 5.0 m/s. Under these conditions, reaching temperatures between 51.0 and 56.2 °C in the well was possible, which is required of the geothermal energy for the solar energy process. A water stream was used as the working fluid in the parabolic trough collector field. During the evaluation stage, the average experimental storage tank temperature achieved by the parabolic trough plant was 93.8 °C on October 23 and 92.9 °C on October 25, 2017. The numerical simulation used to evaluate the performance of the absorption cycle used a generator temperature of 90 °C, a condenser and absorber temperature at 35 °C, and an evaporator temperature of 10 °C. The Coefficient of Performance was calculated as 0.71 under design conditions