Analytical and Experimental Study of Potential Heat Recovery From Household Refrigerators

2004 ◽  
Author(s):  
Jessica Todd
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat ◽  
Tap Water ◽  
Economic Feasibility ◽  
Hot Water ◽  
Coil Design ◽  
Waste Heat Recovery System ◽  
Recovery Potential

Opportunities for waste recovery exist in many types of industrial devices as summarized by Kreith and West [1]. However, no experimental data regarding the potential of heat recovery from household refrigerators have been published in open literature. The decision to implement a heat recovery option depends mostly on convenience and cost. In some cases, however, the decision is difficult because there is a lack of reliable information of the payback for a potential application. This article provides useful information for the design and payback of a waste heat recovery system on a household refrigerator. This paper presents experimental and analytical results of energy recovery potential from the heat rejected by the condenser coils of a household refrigerator. Using a small heat exchanger affixed to the condenser coils, the heat thus recovered can preheat domestic tap water. The analytical study considered three designs: A heat exchanger with the refrigerant condensing on the outside of water pipes, refrigerant on the inside of a counter-flow heat exchanger, and the refrigerant condensing inside a serpentine coil enclosed by a container filled with household tap water. Considering economic feasibility and manufacturing ease, the serpentine coil design was chosen. Experimental data confirmed the heat recovery possibility from the condenser coils. The serpentine coil design can achieve a payback time of 2 to 10 years dependent on whether the domestic hot water uses electric or gas heating.

Electrical and CHP Efficiencies of a 1 MW University Fuel Cell Power Plant

2009 ◽  
Author(s):  
Robert Ryan
Keyword(s):  
Heat Exchanger ◽  
Fuel Cell ◽  
Power Plant ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW fuel cell power plant began operation at California State University, Northridge (CSUN) in January, 2007. The power plant was installed on campus to complement a Satellite Chiller Plant which is being constructed in response to increased cooling demands related to campus growth. The power plant consists of four 250 kW fuel cell units, and a waste heat recovery system which produces hot water for the campus. The waste heat recovery system was designed by CSUN’s Physical Plant Management personnel, in consultation with engineering faculty and students, to accommodate the operating conditions required by the fuel cell units as well as the thermal needs of the campus. A unique plenum system, known as a Barometric Thermal Trap, was created to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is being used to partially supply the campus’ building hot water and space heating requirements. The latent heat is intended for use by an adjacent recreational facility at the University Student Union. This paper discusses plant performance data which was collected and analyzed over a several month period during 2008. Electrical efficiencies and Combined Heat and Power (CHP) efficiencies are presented. The data shows that CHP efficiencies have been consistently over 60%, with the potential to exceed 70% when planned improvements to the plant are completed.

A Study on Waste Heat Recovery in Drain Water with Water-to-Water Heat Exchanger in Barbershops

2012 ◽  
Vol 608-609 ◽  
pp. 1231-1235
Author(s):  
Fang Tian Sun ◽  
Na Wang ◽  
Xiao Gang Gong ◽  
Yun Ze Fan ◽  
De Ying Li
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Hot Water ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Waste Heat Recovery System ◽  
Heat Utilization ◽  
Water Heaters

Heat utilization efficiency of barbershop was about 16.7% in China, because the low-temperature waste water at 30～36°C was directly discharged into sewer. And match of energy grade was not appropriate, because electric water heaters were used to producing hot water at 55～70°C in most of barbershops. A waste heat recovery system with water-to-water heat exchanger (WHR-HE) was presented, according to heat utilization characteristics of barbershop and scientific principle of energy utilization. WHR-HE was analyzed by the first Law of thermodynamics and economics. The analyzed results show that energy consumption can be reduced about 75%, and incremental payback period is less one year for WHR-HE. There is optimal cold side temperature difference of water-to-water heat exchanger.

Research on Waste Heat Recovery in Drain Water of Barbershop

2012 ◽  
Vol 204-208 ◽  
pp. 4229-4233 ◽  
Author(s):  
Fang Tian Sun ◽  
Na Wang ◽  
Yun Ze Fan ◽  
De Ying Li
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Utilization Efficiency ◽  
Drain Water ◽  
Waste Heat Recovery System ◽  
Heat Utilization ◽  
Recovery System ◽  
Heat Recovery System

Drain water at 35°C was directly discharged into sewer in most of barbershop with Electric water heater. Heat utilization efficiency is lower, and energy grade match between input and output is not appropriate in most of barbershops. Two waste heat recovery systems were presented according to the heat utilization characteristics of barbershops and principle of cascade utilization of energy. One was the waste heat recovery system by water-to-water heat exchanger (WHR-HE), and the other is the waste heat recovery system by water-to-water heat exchanger and high-temperature heat pump (WHR-CHEHP). The two heat recovery systems were analyzed by the first and second Laws of thermodynamic. The analyzed results show that the energy consumption can be reduced about 75% for HR-HE, and about 98% for WHR-CHEHP. Both WHR-HE and WHR-CHEHP are with better energy-saving effect and economic benefits.

Heat and Mass Transfer Analysis of Mine Exhaust Air Heat Exchanger

2013 ◽  
Vol 765-767 ◽  
pp. 3018-3022
Author(s):  
Qiong Li ◽  
Yong Sheng Niu ◽  
Yi Xiang Sun ◽  
Zhe Liu
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Energy Resource ◽  
Thermal Calculation ◽  
Heat And Mass Exchange ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Good Energy

As a good energy resource, Mine exhaust air has an important value of recycling. In this paper, the heat and mass exchange mechanism and potential of the mine exhaust air heat exchanger (MEAHE) is mainly researched. The heat exchanger efficiency is affected by water and air temperature and flow in terms of double efficiency method. The result can provide the basis for the further determine the thermal calculation method for MEAHE, and lays the foundation for the mine comprehensive utilization of waste heat recovery system design.

Design and Performance of a Fuel Cell Plant Heat Recovery System

2007 ◽  
Author(s):  
Robert G. Ryan ◽  
Tom Brown
Keyword(s):  
Fuel Cell ◽  
Latent Heat ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

scholarly journals Advance Exergo-Economic Analysis of a Waste Heat Recovery System Using ORC for a Bottoming Natural Gas Engine

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 267 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Jhan Piero Rojas ◽  
Jorge Duarte Forero
Keyword(s):  
Heat Exchanger ◽  
Economic Analysis ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Cost Rate ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

This manuscript presents an advanced exergo-economic analysis of a waste heat recovery system based on the organic Rankine cycle from the exhaust gases of an internal combustion engine. Different operating conditions were established in order to find the exergy destroyed values in the components and the desegregation of them, as well as the rate of fuel exergy, product exergy, and loss exergy. The component with the highest exergy destroyed values was heat exchanger 1, which is a shell and tube equipment with the highest mean temperature difference in the thermal cycle. However, the values of the fuel cost rate (47.85 USD/GJ) and the product cost rate (197.65 USD/GJ) revealed the organic fluid pump (pump 2) as the device with the main thermo-economic opportunity of improvement, with an exergo-economic factor greater than 91%. In addition, the component with the highest investment costs was the heat exchanger 1 with a value of 2.769 USD/h, which means advanced exergo-economic analysis is a powerful method to identify the correct allocation of the irreversibility and highest cost, and the real potential for improvement is not linked to the interaction between components but to the same component being studied.

Flow Rate Optimization of a Linear Concentrating Photovoltaic System

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Tony Kerzmann ◽  
Laura Schaefer
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Storage System ◽  
Water Storage ◽  
Heat Energy ◽  
Hot Water ◽  
Recovery Model ◽  
Waste Heat Recovery System ◽  
Recovery System

The world is facing an imminent energy supply crisis. In order to sustain and increase our energy supply in an environmentally conscious manner, it is necessary to advance renewable technologies. An area of recent interest is in concentrating solar energy systems that use very high efficiency solar cells. Much of the recent research in this field is oriented toward three dimensional high concentration systems, but this research focused on a two dimensional linear concentrating photovoltaic (LCPV) system combined with an active cooling and waste heat recovery system. The LCPV system serves two major purposes: it produces electricity and the waste heat that is collected can be used for heating purposes. There are three parts to the LCPV simulation. The first part simulates the cell cooling and waste heat recovery system using a model consisting of heat transfer and fluid flow equations. The second part simulates the GaInP/GaAs/Ge multijunction solar cell output so as to calculate the temperature-dependent electricity generation. The third part of the simulation includes a waste heat recovery model which links the LCPV system to a hot water storage system. Coupling the multijunction cell model, waste heat recovery model and hot water storage system model gives an overall integrated system that is useful for system design, optimization, and acts as a stepping stone for future multijunction cell photovoltaic/thermal (PV/T) systems simulation. All of the LCPV system components were coded in Engineering Equation Solver V8.425 (EES) and were used to evaluate a 6.2 kWp LCPV system under actual weather and solar conditions for the Phoenix, AZ, region. This evaluation was focused on obtaining an optimum flowrate, so as to produce the most electrical and heat energy while reducing the amount of parasitic load from the fluid cooling system pump. Under the given conditions, it was found that an optimal cooling fluid flowrate of 4 gal/min (2.52×10-4m3/s) would produce and average of 45.9 kWh of electricity and 15.9 kWh of heat energy under Phoenix conditions from July 10–19, 2005. It was also found that the LCPV system produced an average of $4.59 worth of electrical energy and displaced $0.79 worth of heat energy, while also displacing a global warming potential equivalent of 0.035 tons of CO2 per day. This simulation uses system input parameters that are specific to the current design, but the simulation is capable of modeling the LCPV system under numerous other conditions.

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