Novel Energy Efficient and Environmentally Friendly Space-Conditioning Systems: Challenges and Opportunities

Author(s):  
Srinivas Garimella

Abstract This paper discusses several different approaches to increase the energy efficiency and decrease the environmental impact of space-conditioning systems. The use of microchannel components and hydronic coupling is presented as a method to drastically reduce the size and refrigerant inventories of the refrigerant-carrying components of vapor-compression heat pumps. Design aspects of heat pumps using carbon dioxide, a natural refrigerant with minimal environmental impact, are discussed, and novel component geometries that offer compactness are presented. The advantages of absorption heat pumps using waste heat and natural gas are discussed, and innovative component designs are presented. It is believed that these innovations will hasten the commercialization of these environmentally benign alternatives to CFC- and HCFC-based vapor-compression systems. The environmental benefits of waste heat-driven absorption chillers are quantified in terms of the energy savings, greenhouse gas emission reductions, and installed electric power reductions. Ground coupling of these heat pumps is also discussed, with specific examples of the performance improvement over similar air-coupled heat pumps.

MRS Bulletin ◽  
2022 ◽  
Author(s):  
Shuang Cui ◽  
Adewale Odukomaiya ◽  
Judith Vidal

Abstract Because of the complexity of modern buildings—with many interconnected materials, components, and systems—fully electrifying buildings will require targeted R&D and efficient coordination across those material, component, and system levels. Because buildings that consume the smallest amount of energy are easier to electrify, energy efficiency is a crucial step toward fully electrified buildings. Materials advances will play an important role in both reducing the energy intensity of buildings and electrifying their remaining energy use. Materials are currently being explored, discovered, synthesized, evaluated, optimized, and implemented across many building components, including solid-state lighting; dynamic windows and opaque envelopes; cold climate heat pumps; thermal energy storage; heating, ventilating, and air conditioning (HVAC); refrigeration; non-vapor compression HVAC; and more. In this article, we review the current state-of-the-art of materials for various buildings end uses and discuss R&D challenges and opportunities for both efficiency and electrification. Graphical abstract


Urban Health ◽  
2019 ◽  
pp. 369-374 ◽  
Author(s):  
Jie Yin ◽  
John D. Spengler

Green building design has emerged as a global force, with one green building standard reporting more than 3.5 billion square feet certified worldwide. Green buildings focus on reducing environmental impact through improved water storage, reducing environmental perturbation, and reducing energy usage. Although the environmental benefits of green building design are now well established, it is only more recently that the field has come to appreciate the health benefits of green building design. This chapter discusses the green building movement and the challenges and opportunities it represents, with lessons that can be learned and are generalizable to urban health scholarship and action worldwide.


2014 ◽  
Vol 493 ◽  
pp. 93-98 ◽  
Author(s):  
Kasni Sumeru ◽  
Luga Martin ◽  
Farid Nasir Ani ◽  
Henry Nasution ◽  
Farid Nasir Ani

There are two ejector configurations described in the present study: ejector refrigeration cycle and the ejector as an expansion device. The use of waste heat from the car engine and industry as a heat-driven energy for air conditioning system in automobile and building can save energy. Although the ejector refrigeration cycle has a low COP, the use of waste heat as a heat-driven energy incurs a lower operational cost compared with vapor compression refrigeration system. In addition, an ejector as an expansion device can be applied in the vapor compression refrigeration cycle to improve the performance system.


Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2385 ◽  
Author(s):  
Ujué Fresán ◽  
Winston J. Craig ◽  
Miguel A. Martínez-González ◽  
Maira Bes-Rastrollo

Current dietary patterns are negatively affecting both the environment and people’s health. Healthy diets are generally more environmentally friendly. However, few studies have focused on the health consequences of diets with low environmental impact. We analyzed differences in the dietary composition (types of food, macro- and micro-nutrients) of those diets with high and low environmental impact, according to greenhouse gas emission and resources use (water, land and energy) using data from a Spanish cohort (17,387 participants), collected by means of a validated food frequency questionnaire. Cox analyses were used to assess the association of dietary environmental impact with total mortality risk. At a given level of energy intake, diets with lower environmental impact contained higher amounts of plant-based foods and lower levels of animal-derived products. Less polluting diets involved higher amounts of polyunsaturated fats and dietary fiber and lower amounts of saturated fats and sodium. However, diets associated with less environmental damage also contained more added sugars, but lower levels of vitamin B12, zinc and calcium. We did not detect any association between dietary environmental impact and risk of mortality. Diets should not only produce minimal environmental impact, but the maximum overall benefits for all key dimensions encompassed in sustainable diets.


Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 752 ◽  
Author(s):  
Rabiatul Adawiyah Ali ◽  
Nik Nor Liyana Nik Ibrahim ◽  
Hon Loong Lam

The generation of municipal solid waste (MSW) is increasing globally every year, including in Malaysia. Approaching the year 2020, Malaysia still has MSW disposal issues since most waste goes to landfills rather than being utilized as energy. Process network synthesis (PNS) is a tool to optimize the conversion technologies of MSW. This study optimizes MSW conversion technologies using a PNS tool, the “process graph” (P-graph). The four highest compositions (i.e., food waste, agriculture waste, paper, and plastics) of MSW generated in Malaysia were optimized using a P-graph. Two types of conversion technologies were considered, biological conversion (anaerobic digestion) and thermal conversion (pyrolysis and incinerator), since limited data were available for use as optimization input. All these conversion technologies were compared with the standard method used: landfilling. One hundred feasible structure were generated using a P-graph. Two feasible structures were selected from nine, based on the maximum economic performance and minimal environmental impact. Feasible structure 9 was appointed as the design with the maximum economic performance (MYR 6.65 billion per annum) and feasible structure 7 as the design with the minimal environmental impact (89,600 m3/year of greenhouse gas emission).


2012 ◽  
Vol 9 (2) ◽  
pp. 65
Author(s):  
Alhassan Salami Tijani ◽  
Nazri Mohammed ◽  
Werner Witt

Industrial heat pumps are heat-recovery systems that allow the temperature ofwaste-heat stream to be increased to a higher, more efficient temperature. Consequently, heat pumps can improve energy efficiency in industrial processes as well as energy savings when conventional passive-heat recovery is not possible. In this paper, possible ways of saving energy in the chemical industry are considered, the objective is to reduce the primary energy (such as coal) consumption of power plant. Particularly the thermodynamic analyses ofintegrating backpressure turbine ofa power plant with distillation units have been considered. Some practical examples such as conventional distillation unit and heat pump are used as a means of reducing primary energy consumption with tangible indications of energy savings. The heat pump distillation is operated via electrical power from the power plant. The exergy efficiency ofthe primary fuel is calculated for different operating range ofthe heat pump distillation. This is then compared with a conventional distillation unit that depends on saturated steam from a power plant as the source of energy. The results obtained show that heat pump distillation is an economic way to save energy if the temperaturedifference between the overhead and the bottom is small. Based on the result, the energy saved by the application of a heat pump distillation is improved compared to conventional distillation unit.


Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 954 ◽  
Author(s):  
Hanne Kauko ◽  
Daniel Rohde ◽  
Armin Hafner

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.


Author(s):  
Antonio Agresta ◽  
Antonella Ingenito ◽  
Roberto Andriani ◽  
Fausto Gamma

Following the increasing interest of aero-naval industry to design and build systems that might provide fuel and energy savings, this study wants to point out the possibility to produce an increase in the power output from the prime mover propulsion systems of aircrafts. The complexity of using steam heat recovery systems, as well as the lower expected cycle efficiencies, temperature limitations, toxicity, material compatibilities, and/or costs of organic fluids in Rankine cycle power systems, precludes their consideration as a solution to power improvement for this application in turboprop engines. The power improvement system must also comply with the space constraints inherent with onboard power plants, as well as the interest to be economical with respect to the cost of the power recovery system compared to the fuel that can be saved per flight exercise. A waste heat recovery application of the CO2 supercritical cycle will culminate in the sizing of the major components.


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