Renewable Energy: Solar-Cooling Technologies

Renewable Energy Technologies: Solar-Cooling

• Solar-cooling technologies use solar energy for refrigeration, air conditioning, and food preservation.
• A solar-cooling example is a refrigeration system with solar collectors providing heat input.

Solar Cooling Systems

• Absorption Cycle: A diagram shows the components: condenser, vaporizer, absorber, generator, solution throttle valve, restrictor valve. These components are part of a closed-circuit system. Relevant heat is labeled (Qcond, Qvap, Qabsorb).

• Solar-Cooling Technologies: Use solar energy for cooling.

• Example Systems:

  • Refrigeration systems combined with solar collectors provide heat input.
  • Diagrams illustrate the system, showing components like solar collectors, hot storage, cold storage, and a user area.

Additional Solar-Cooling Systems

• Electric Solar: Uses photovoltaic modules and inverters for power, and an electric refrigerator for cooling. This has a battery storage component.
• Thermal Solar: Uses thermal collectors and a thermal storage component. The diagram shows components like solar collectors, storage, and a user zone. A thermal component is included.
• Diagrams illustrate these types of systems, connecting the components in a circuit for cooling applications (cooling and dehumidification).

Traditional Electric Chiller

• A traditional electrically powered chiller with photovoltaic modules is depicted. This diagram details the photovoltaic module input and the conventional compressor, condenser, and evaporator components.

Advantages of Solar Cooling

• Reduces electricity consumption for air conditioning in buildings.
• Reduces emissions of pollutants (NOx, SO2), and greenhouse gases (CO2).
• Overlap between solar radiation availability and cooling demand.
• Large solar collector surfaces enhance winter heating/DHW (Domestic Hot Water) contribution.

Critical Issues of Solar Cooling

• Installation costs are greater than traditional systems.
• Heat rejection is a crucial aspect.
• Limited knowledge base of the technology.
• The solar-cooling system may not be self-sufficient.

Absorption Cycle: Max Ideal COP

• Mathematical formulas show the ideal Coefficient of Performance (COP) calculations for different parameters in an absorption cycle.
• Equations demonstrate the relationship between heat transfer (q0, q8, qC,), temperatures (To, T_AMB, T_G), and COP.

Absorption Systems and Subsystems

• Refrigerating absorption systems are present. Desiccant evaporative cooling is a type of system.
• DEC (Desiccant Evaporative Cooling) Systems: Open circuit systems use to condition air from external environments. Combining dehumidification and evaporative cooling in AHUs (air handling units.)

Sorption Technologies

• Absorption is the process of incorporating a substance into another phase (gases absorbed by a liquid).
• Adsorption uses solids to adhere or bond other substances to their surfaces.
• Desiccant cooling is a type of thermally activated technology, using the principles of absorption and adsorption.

Solar-Cooling Systems, Based on Absorption Chillers

• Closed-circuit systems are used to produce chilled water.
• They combine with various distribution methods (air treatment units, etc.).
• Absorption chillers are single or double effect, using lower or higher temperature inputs.

Thermally Activated Cooling Technologies: Summary

• Tables summarizing different sorption technologies, including types, heat sources, refrigeration capacity, cooling methods, and COP ranges.
• Specific details about lithium bromide-water absorption systems, including cooling temperature, heat source temperature, cooling capacity, thermal COP, and other characteristics. The table distinguishes single, double, and triple-effect absorption chillers.

Coefficient of Performance (COP) in Absorption Chillers

• Diagrams show the COP variation with heat supply temperature for single effect, double effect, and triple effect absorption chillers. Diagrams display the relationship between the heat supply temperature and COP.

Desiccant Cooling (DEC) Systems

• The system uses desiccants for air conditioning.
• It utilizes an open cycle, operating with humid air, and does not require refrigerants to cool.
• The system uses external heat source and internally transfers heat to achieve cooling.
• The system features a dehumidifier to reduce humidity.

Materials for Adsorption Chillers

• Lists different adsorbents (e.g., silica gel, zeolite) and refrigerants (e.g., water, methanol).
• Different characteristics (heat of adsorption, toxicity, generation temperature) for these materials are presented in the context of applications.

Diagrams and Schematics

• Various diagrams illustrating the different types of solar cooling systems (absorption, adsorption). The diagrams typically show components involved in the systems, such as heat exchangers, condensers, evaporators, and regulators.

Air Dehumidification with Solid Desiccants

• Air dehumidification process using solid dessicant is shown in a diagram, with details of the regeneration cycle.

DEC Systems (Desiccant Evaporative Cooling)

• Open circuit systems for direct air treatment, combining dehumidification and evaporative cooling.
• Applied to air handling units (AHUs) requiring adequate air distribution systems.