scholarly journals Techno-Economic Assessment of a Hybrid Gas Tank Hot Water Combined Heat and Power System

2021 ◽  
Vol 13 (23) ◽  
pp. 13040
Author(s):  
Brent B. Skabelund ◽  
Joseph Elio ◽  
Ryan J. Milcarek

Combined heat and power (CHP) systems with an integrated solid oxide fuel cell (SOFC) is a promising technology to increase overall efficiency of traditional residential combustion systems. One potential system is gas tank hot water heaters where partial oxidation of the fuel serves as a means of fuel reforming for SOFCs while producing thermal energy for heating water. In this study, a residential hybrid gas tank hot water heater with an integrated SOFC model was developed and a thorough techno-economic analysis was performed. Fuel-rich combustion characterization was performed at equivalence ratios 1.1 to 1.6 to assess synthesis gas production for the SOFC. The effect of fuel utilization and operating voltage of the model SOFC stack were analyzed to provide an in-depth characterization of the potential of the system. CHP and electrical efficiencies over >90% and >16% were achieved, respectively. The techno-economic analysis considers the four major census regions of the United States to evaluate regional savings based on respective utility costs and hot water demand. The results show the hybrid system is economically feasible for replacement of an electrical water heater with the longest payback period being approximately six years.

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 548
Author(s):  
Kadir Amasyali ◽  
Jeffrey Munk ◽  
Kuldeep Kurte ◽  
Teja Kuruganti ◽  
Helia Zandi

Electric water heaters represent 14% of the electricity consumption in residential buildings. An average household in the United States (U.S.) spends about USD 400–600 (0.45 ¢/L–0.68 ¢/L) on water heating every year. In this context, water heaters are often considered as a valuable asset for Demand Response (DR) and building energy management system (BEMS) applications. To this end, this study proposes a model-free deep reinforcement learning (RL) approach that aims to minimize the electricity cost of a water heater under a time-of-use (TOU) electricity pricing policy by only using standard DR commands. In this approach, a set of RL agents, with different look ahead periods, were trained using the deep Q-networks (DQN) algorithm and their performance was tested on an unseen pair of price and hot water usage profiles. The testing results showed that the RL agents can help save electricity cost in the range of 19% to 35% compared to the baseline operation without causing any discomfort to end users. Additionally, the RL agents outperformed rule-based and model predictive control (MPC)-based controllers and achieved comparable performance to optimization-based control.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mehdi Jahangiri ◽  
Esther T. Akinlabi ◽  
Sam M. Sichilalu

Solar water heaters (SWHs) are one of the most effective plans for general and easy use of solar energy to supply hot water in domestic and industrial sectors. This paper gives the first-ever attempts to assess the optimal localization of SWHs across 22 major cities in Zambia, as well as determine the possibility of hot water generation and model the greenhouse gas (GHG) emission saving. The climate data used is extracted by using the MeteoSyn software which is modeled in TSOL™. Results show the high potential of GHG emission reduction due to nonconsumption of fossil fuels owing to the deployment of SWHs, and three cities Kabwe, Chipata, and Mbala had the highest GHG mitigation by 1552.97 kg/y, 1394.8 kg/y, and 1321.39 kg/y, respectively. On average, SWHs provide 62.47% of space heating and 96.05% of the sanitary hot water requirement of consumers. The findings have shown the potential for the deployment of SWHs in Zambia. The techno-enviro study in this paper can be used by the policymakers of Zambia and countries with similar climates.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.


2010 ◽  
Vol 129-131 ◽  
pp. 463-466
Author(s):  
Li Li Zhao ◽  
Zhi Jun Zhang ◽  
Shi Wei Zhang

The 3D physical model of the electrical water heater was built. The water-heater performance was resolved by computer fluid dynamics simulation (CFD). The heater performance is characterized by a new method rather than that the discharge efficiency, extraction efficiency and fraction of heat recoverable. The new method is based on the constant discharge water temperature and rate for end user, 5L/min and 43°C that include the hot water from EWH and cold water from outside EWH. But the water discharge rate from EWH was variable as the water temperature discharge from EWH was variable. Compared with the traditional method, it is more close to the user using reality condition.


Green ◽  
2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Brian Norton

AbstractSolar water heating can be considered to be an established mature technology. The achievement of this status is the outcome of over a century of system development that culminated with a flourish of innovation in the last thirty years. Drivers for research and development have been achieving economic viability by devising systems that, for specific applications in particular climate contexts produced more hot water per unit cost. Reductions in both initial capital and installation costs have been achieved as well as in those associated with subsequent operation and maintenance. Research on solar water heating is discussed with the emphasis on overall systems though some key aspects of component development are also outlined. A comprehensive taxonomy is presented of the generic types of solar water heater that have emerged and their features, characteristics and performance are discussed.


2005 ◽  
Vol 297-300 ◽  
pp. 2320-2326
Author(s):  
Dong Jo Yang ◽  
Jae Yeol Kim ◽  
Jae Ho Han

The main purpose of this investigation was to evaluate the performance of the solar hot water heater for dwellings in a long period of time. In order to evaluate the performance, there were 11 solar hot water heaters located in Gwangju Chosun University examined for their performance in 30 month period as a long term. The specific monitoring systems of each heater were constructed for the demonstrational research and the data base associated to each monitoring systems were assembled for an extensive analysis for variety of data obtained. The demonstrational experiments were conducted through following the routine procedures of 4 specific tests (the replicated drainage test, the daily drain test, the daily agitation test, the short-term test). The performance evaluation was based on the performances in insulating and solar collecting and the experimental routines and the performance experiments had incorporated the consumers’ use and need of the product. The ultimate goals of this investigation were to achieve consumers’ trust on the products and to promote the extensive distributions of the solar hot water heaters. The demonstrational research of this investigation was to evaluate the performance of the solar hot water heater for the residents for a long period of time. This research will be continued extensively.


Author(s):  
Gunnar Tamm ◽  
J. Ledlie Klosky ◽  
Jacob Baxter ◽  
Luke Grant ◽  
Isaac Melnick ◽  
...  

Electrical power generation in austere settings, such as combat zones, places a heavy burden on the US Army; high costs in both dollars and lives lost require that every drop of fuel be used effectively and efficiently. In remote locations such as combat outposts (COPs) and small forward operating bases (FOBs) in Afghanistan, electrical power derived from the Army’s standard Advanced Medium Mobile Power Sources (AMMPS) generator is even used to heat water for showers and heat living spaces. This heating requires conversion of thermal energy to mechanical energy, which is then converted to electrical energy and back to heat. Thus, a significant fuel savings could be realized through the more efficient production of heat. A combined heat and power system is proposed; efficiency is increased by routing the generator exhaust through simple ducting to a standard gas hot water heater to produce hot water with waste heat. With funding from the U.S. Army Rapid Equipping Force, cadets and faculty at the United States Military Academy designed, built and tested a system for under $1,000 in parts which was readily coupled to a 5 kW AMMPS generator to produce hot shower water. Results indicate a possible fuel savings of 1500–2000 gallons per year, 20–35% increased fuel utility, and the ability to provide 10–20 five gallon showers during every 5 hours of operation of each 5 kW generator. At a fuel cost of $20–50 per gallon in the deployed environment, and considering the large inventory of deployed generators, the payback for the Army could be tremendous.


1996 ◽  
Vol 118 (2) ◽  
pp. 73-80 ◽  
Author(s):  
A. H. Fanney ◽  
B. P. Dougherty

An increasing number of utilities control the supply of power to residential water heaters as one means of reducing peak electrical demand. Water heaters operated in this manner are referred to as off-peak water heaters. Several utilities are also considering the use of solar domestic water heaters as an additional means of limiting power demand during times of greatest electrical usage. The research described within this paper quantifies the variation in thermal efficiency attributable to subjecting residential electrical water heaters to various off-peak and water removal schedules and, thus, forms a basis of comparison to which the thermal efficiency of solar water heaters or other water heating technologies may be compared. Laboratory tests, where the off-peak period and hot water draw schedule were varied, were conducted on two residential storage water heaters. A computer model of an electric water heater was developed and validated. The laboratory tests and the model were used to quantify the effect that various off-peak and hot water draw schedules have on water heater thermal efficiency. Thermal efficiency was found to vary up to seven percent for water heaters which meet the present minimum efficiency standards as specified within the National Appliance Energy Conservation Act. The energy factor, as measured using the Department of Energy Test Procedure for Water Heaters, is shown to be independent of the off-peak schedule because of a “normalizing” that occurs as part of the calculation procedure.


Author(s):  
Edward W. Saltzberg

Our Office Had Two Condominium Litigation Cases That Had A Number Of Construction Defects. One Was A Luxury Complex And One Was A Moderately Priced Project. However, There Were Two Common Allegations In Both Cases. These Allegations Were That The Occupants Complained That They Did Not Have Sufficient Hot Water And That The Water Heater Was Not Able To Provide A Sufficient Quantity Of Hot Water. We Prepared Calculations On Both Of The Water Heater Systems To Determine If They Were Undersized. The Calculations Determined That The Water Heater Assembly Of Both Installations Were Liberally Sized And Should Have Been Able To Maintain Design Temperature All The Time, Even At Peak Use. To Ensure That The Water Heaters Were Both Operating Correctly, We Had The Water Heater Manufacturer Come Out And Service The Heaters On Both Systems. Both Systems Were Operating Properly.


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