Residential and Commercial Buildings Waste Heat Recovery

Commercial and residential buildings need different energy resources to meet the human living and purpose operation requirement. These buildings required hot and cold water, space heating and cooling, cooking, water supply pumps, air and gas supply compressors, power generation equipment, and electricity to operate most of the appliances and mechanical equipment. Waste heat recovery in buildings refers to the process of capturing and utilizing the excess heat generated by various building systems and equipment, such as HVAC units, space heating furnaces, cooking appliances, and thermal solar radiation through windows. This low grade recovered heat can then be reused for other heating or cooling purposes, reducing energy consumption and increasing overall energy efficiency, thereby reducing overall energy consumption and its impact on the carbon footprint.

There are several ways to implement waste heat recovery in buildings. One common method is through heat exchangers, which transfer heat from the exhaust air or waste water to incoming fresh air or cold water. This can help preheat or precool the incoming air or water, reducing the load on heating or cooling systems. Another approach is to use heat pumps, which can extract heat from low-temperature sources (such as air, water, or the ground) and upgrade it to a higher temperature level for space heating or hot water production. Heat pumps are highly efficient and can provide significant energy savings especially areas that has severe winter and summer climates. The exhaust hot air in summer can be used for superheating the refrigerant after leaving the evaporator coil and the cold air in winter can be used to subcooled the refrigerant after leaving the condenser, both methods are useful for increasing the heat pump refrigeration cycle coefficient of performance. In some cases, waste heat can also be used for other purposes, such as powering absorption chillers for cooling or generating electricity through combined heat and power (CHP) systems. These systems simultaneously produce both useful heat and electricity from a single fuel source.

Waste heat recovery technologies in buildings can range from basic heat exchangers to more advanced systems like heat pumps, absorption chillers, and thermoelectric generators. The appropriate technology choice depends on factors such as the amount and temperature grade of waste heat available, the building's energy needs, and the cost-effectiveness of the system. Building. One of the most recent building window design by Dr. Mohamed Ibrahim Hassan Ali research team is the Residential and Commercial Buildings Multifunction Windows (BMFW).

Implementing waste heat recovery in commercial and residential buildings can contribute to sustainable energy practices, help businesses achieve their energy efficiency goals, and promote a greener living environment.


Multi-function Windows (MFW)

(Dr. Mohamed Ibrahim Hassan Ali)

The proposed design implements semi-transparent laminates PV, water circulation gap, and air gap to be sandwiched in glazing windows for producing electricity and hot water in addition to the building space cooling load reduction. The glazing multi-function window is a type of window that is designed with multiple functionalities. It typically has a multi-layered glazing system that enhances its energy efficiency by reducing heat transfer and minimizing air leakage. Additionally, it may have integrated features like adjustable tinting or shading capabilities, which allow for control of the amount of light and heat that enters the space. Adding the water layer will absorb the undesired thermal solar radiation and cool down the semi-transparent PV, which will lead to increase the PV performance, reduce the indoor cooling load and provide hot water to be used in the building. In addition it offers sound insulation properties, providing a quieter indoor environment. Overall, these windows provide improved comfort, energy savings, and customizable functionality for the users. The windos configuration for Multi-function window (MFW), semi-transperint PV window (STPW), and standard duble galzing window (DGW) are shown in the figure below.


The power gain (STPV), heat gain, office cooling load, and lightinig load results for the three type window (case 1 (C1), case 2 (C2), and case 3 (c3)) are shown in the following figure. It is opvious that the MFW provide a significant heat gain and office load reduction; however, it shows bout 15% reduction in the STPV output because of the water layer attinuation.