Energy systems in different industrial applications including automotive applications experience between 20 to 50 percent of raw energy input as waste heat. in the form of hot exhaust gases, hot cooling water and lost heat from hot equipment surfaces including heated products. Continued efforts to improve systems energy efficiency, recovering waste heat losses provide attractive opportunities for reduced emission and less costly energy resources. This invention introduces other methods for higher performance of existing energy consuming systems by optimizing the performance of some of the system modules that contributes to the waste energy. in turn reduce energy consumption of these systems, reduces its operating cost, damages to the population health by reducing pollution improving the environment quality, and also reduces the cost of health care. Improving efficiency of the module's' which contribute large percentage of waste energy as by-product from the operation of these systems can improve the system efficiency.

Systems and methods for controlling conditions in an enclosed space, such as a data center, or for providing cooling to a device, can include using a Liquid-to-Air Membrane Energy Exchanger (LAMEE) as an evaporative cooler. The LAMEE or exchanger can cool water to the outdoor air wet bulb temperature in a cooling system disposed outside of the enclosed space or device. The reduced-temperature water can be delivered to the enclosed space or device or can cool a coolant that is delivered to the enclosed space or device. The air in the enclosed space, or one or more components in the enclosed space, can be cooled by delivering the reduced-temperature water or coolant to the enclosed space, rather than moving the supply air from the enclosed space to the cooling system. In an example, the cooling system can include one or more cooling coils, upstream or downstream of the LAMEE.

A heat exchanger for exchanging heat between first and second duct portions of a ventilation system includes first and second heat pipe portions in the first and second duct portions, respectively. Each heat pipe portion can be a heat pipe subassembly including one or more vertical heat pipes fluidly coupled to top and bottom headers, which are respectively connected to the top and bottom headers of the other subassembly to form a refrigerant loop. One or more flow restrictors can block air flow through a respective section of the first or second duct portion. The blocked section can be operatively aligned with a segment of the respective heat pipe portion along which there is a low probability of refrigerant phase change. Each flow restrictor can be an adjustable damper. The damper(s) can be selectively opened and closed as the ventilation system switches between heating and cooling modes.