The Thermal Performance of Residential Electric Water Heaters Subjected to Various Off-Peak Schedules

1996 ◽  
Vol 118 (2) ◽  
pp. 73-80 ◽  
Author(s):  
A. H. Fanney ◽  
B. P. Dougherty
Keyword(s):  
Thermal Efficiency ◽  
Laboratory Tests ◽  
Test Procedure ◽  
Hot Water ◽  
Department Of Energy ◽  
Water Heater ◽  
Domestic Water ◽  
Peak Period ◽  
Water Heaters ◽  
Solar Water Heaters

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.

scholarly journals Assessment and Modeling of Household-Scale Solar Water Heater Application in Zambia: Technical, Environmental, and Energy Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mehdi Jahangiri ◽  
Esther T. Akinlabi ◽  
Sam M. Sichilalu
Keyword(s):  
Fossil Fuels ◽  
Hot Water ◽  
Climate Data ◽  
Ghg Emission ◽  
Water Heater ◽  
Ghg Mitigation ◽  
Solar Water ◽  
Water Heaters ◽  
Industrial Sectors ◽  
Solar Water Heaters

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.

scholarly journals Thermal efficiency and cost analysis of solar water heater made in Rwanda

2018 ◽  
Vol 37 (3) ◽  
pp. 1147-1161 ◽  
Author(s):  
Esdras Nshimyumuremyi ◽  
Wang Junqi
Keyword(s):  
Cost Analysis ◽  
Thermal Efficiency ◽  
Solar Water Heater ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water Heating ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Made In

Solar water heating is a technology of capturing the energy from the sun's radiation for the purpose of raising the temperature of water from water supply temperature to the desired higher temperature depending on the use. There are many views and discussions on the questions of thermal efficiency of solar water heaters and their associated cost, especially different customers/users want to replace their existing conventional water heating energy by solar water heating systems. In this present paper, a deep investigation has been accomplished to determine thermal efficiency and cost analysis of solar water heater made in Rwanda. During manufacturing of solar water heater, the collector was the main part to emphasize on. The high efficiency of the system was achieved by replacing galvanized iron sheet by aluminum sheet slotted and black painted as an absorber plate. The ambient temperature and average solar radiation of the three sites where solar water heaters are installed were investigated. The used materials, specifications and sizing were discussed in this paper.

Effect of Surface Roughness and Micro-Grooves on Condensed Water Removal in Latent Heat Recovery Heat Exchanger

2011 ◽  
Author(s):  
Kenta Kimoto ◽  
Hitoshi Asano ◽  
Masafumi Sakurai ◽  
Tetsuro Hamada ◽  
Makoto Hirotsu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Latent Heat ◽  
Thermal Efficiency ◽  
Heat Recovery ◽  
Horizontal Tube ◽  
Hot Water ◽  
Water Heater ◽  
Water Heaters ◽  
Condensed Water

Hot-water supply has high percentage of energy consumption in Japanese civilian sector. Gas water heaters are used in most cases. Therefore, improvement in thermal efficiency of a gas water heater is an important issue for energy saving. In order to improve thermal efficiency of a gas water heater, an additional heat exchanger is required for latent heat recovery from exhaust humid combustion. The purpose of this study is to develop a compact latent heat recovery heat exchanger with a simple configuration. It is necessary for compactness to reduce the gap between the heat transfer tubes. However, the narrow gap will cause stagnation of condensed water. In order to remove the condensed water from horizontal tube bank, three kinds of tubes with different surface treatments, polished tubes, unpolished tube, and smooth tube with circular micro-grooves, were examined. As the result, condensed water was easily removed by the groove with the 0.7mm depth, to avoid the formation of water bridges between tubes. The effect could lead to no deterioration in the heat transfer performance by decreasing the tube clearance to 1.0mm.

scholarly journals Energy Efficiency for Social Buildings in Morocco, Comparative (2E) Study: Active VS. Passive Solutions Via TRNsys

Inventions ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Fatima Zohra Gargab ◽  
Amine Allouhi ◽  
Tarik Kousksou ◽  
Haytham El-Houari ◽  
Abdelmajid Jamil ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Savings ◽  
Building Envelope ◽  
Hot Water ◽  
Solar Water Heater ◽  
Water Heater ◽  
Climatic Zones ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters

This paper aims to highlight the potential of solar water heater installations in Morocco. The project involves the comparison of active and passive solutions for energy efficiency in buildings. To this end, a numerical simulation model of solar water heater installations is created under TRNsys. Three hot water demand scenarios (Low, Standard, and High) were taken into account for the six climatic zones defined in the Moroccan thermal regulation of constructions. The same software (TRNsys) is used to model a pilot building consisting of 16 flats. Energy efficiency actions have been applied to the building envelope (insulation and glazing) and simulations are made for the six areas. The simulation results comparing energy and financial savings show the influence of subsidized gas prices on solar water heaters’ relevance despite significant energy savings. This work proves that solar water heaters will be a primary obligation for Morocco, taking into account changes in butane gas prices.

Comparative Study of the Thermal Performance of Two Thermosiphon Solar Water Heaters System

2020 ◽  
Vol 9 (3) ◽  
pp. 401-410
Author(s):  
Blaise Kamenan Koua ◽  
Paul Magloire Ekoun Koffi ◽  
Prosper Gbaha
Keyword(s):  
Thermal Performance ◽  
Weather Conditions ◽  
Glass Wool ◽  
Hot Water ◽  
Experimental Investigations ◽  
Coconut Fiber ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters

 The aim of this study is to present the comparative results of experimental investigations of the thermal performance of two thermosiphon solar water heaters system (SWHS). The first uses the coconut fiber (CF), a local vegetable and the second, the glass wool (GW), an imported and expensive material, as thermal insulations. The maximum instantaneous efficiencies are, respectively, 65.30 % and 58.7% with glass wool and coconut fiber while the mass flow rate values are, respectively, 0.0098 kg/s and 0.0078 kg/s with glass wool and coconut fiber. In addition, the calculated average values of F’(τα) and F’UL are, respectively, 0.79 and 5.86 Wm-2°C for the coconut fiber collector and 0.8 and 5.26 Wm-2°C for the glass wool collector. The average heat exchanger effectiveness obtained for the two SWHS are superior to 50%. As an environment-friendly and renewable material, coconut fiber is particularly suitable for thermal insulation in order to save energy. The experimental results show the ability of the constructed solar water heater in providing hot water suitable for maternity, hotels, households and encourage its implementation and utilization on a broad scale. The SWHS can be used in any weather conditions. ©2020. CBIORE-IJRED. All rights reserved

Virtual test bench for the design of control strategies for water heaters

2021 ◽  
pp. 1-36
Author(s):  
André Quintã ◽  
Jonathan Oliveira ◽  
Jorge Ferreira ◽  
Vítor Costa ◽  
Nelson Martins
Keyword(s):  
Test Bench ◽  
Control Strategies ◽  
Heat Pumps ◽  
Open Loop ◽  
Hot Water ◽  
Hardware In The Loop ◽  
Water Heater ◽  
Domestic Water ◽  
Virtual Test ◽  
Water Heaters

Abstract An innovative methodology and a virtual test bench are proposed to support the design of water heaters' control strategies. This platform allows to speed up the development and evaluation of control systems even before the existence of prototypes or real test environments. By simulating the environmental conditions and the state of the different device components, it will be possible to detect and correct possible initial errors in the control system design which can be time consuming and costly due to subsequent modifications to the system or equipment components. The architecture of the proposed system establishes four operating modes, open loop data acquisition, real time simulation, hardware-in-the-loop simulation, and test of the complete real system, the incorporation of these functionalities in the same platform is not reported in the literature for domestic water heaters. The virtual test bench was designed to accommodate different water heaters including, but not limited to, gas, electric and heat pumps, for instantaneous hot water production or including hot water storage. The prototype of the virtual test bench is described emphasizing the hardware-in-the-loop methodologies and embedded control. The particular case study of a tankless gas water heater is presented implementing the different operation modes in the virtual test bench. The water heater models, control strategies, simulation and experimental data are presented and discussed.

scholarly journals Development of a Design Tool for Sizing and Optimizing Thermosyphon Solar Water Heater Systems: A Case Study for Tripoli-Libya

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
M.J.R Abdunnabi ◽  
D.L D.L. Loveday ◽  
J.A Wright
Keyword(s):  
Weather Conditions ◽  
Design Tool ◽  
Hot Water ◽  
Commercial Application ◽  
Water Heater ◽  
Water Load ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters

Thermosyphon solar water heaters can be considered the most popular solar technology for supplying households with the needed hot water for domestic purposes. However, sizing these systems is mainly based on experience and trial methods, these methods were established more on intuition instead of scientific approaches. This paper is aimed at studying the sizing of thermosyphon systems through the development of a dedicated generic design tool. The tool can be utilized by manufacturers and engineers to arrive at optimized systems designed according to the operating and weather conditions of certain geographical locations. The design tool is implemented in this study to find the optimum system design that fits households in Libya (as a case study in this work) and accounts for the weather conditions of Tripoli and a simple, but representative, hot water load pattern. Two different sizes of thermosyphon systems covers hot water load of 180 lit and 240 lit, and two different configurations with vertical and horizontal tanks are studied and the best fit designs are obtained. The design tool has shown a great potential, and with further development and validation would be capable of widespread commercial application.

Thermal Properties Study of a Solar Water Heater Tank with a Mantle Exchanger

2014 ◽  
Vol 3 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Mourad Chikhi ◽  
Rabah Sellami ◽  
Nachida Kasbadji Merzouk
Keyword(s):  
Heat Exchanger ◽  
Renewable Energy Sources ◽  
Supply And Demand ◽  
Research Work ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Incentive Programs ◽  
Water Heaters ◽  
Solar Water Heaters

The development and use of renewable energy sources and technologies are becoming vital for the management of energy supply and demand. For development solar water heaters, the incentive programs are supported by the Algerian government to generalize the using of this kind of energy especially in Sahara. This study is a part of program to develop a new solar water heater in UDES (Algeria). In this research work, the thermal performance of a solar water heater with a mantle heat exchanger is investigated numerically using Comsol Multyphysics software. The objective is to investigate the influence of the mantle heat exchanger thickness on the performance of solar water heaters. The results show, for 160 liters capacity of the solar water heaters tank, the 13mm of the heat exchanger thickness leads to improve the efficiency of the solar water heater.

scholarly journals Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier
Keyword(s):  
Heat Pump ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
Design Tool ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Water Heaters

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.

Characteristic Heat Removal Efficiency for Thermosyphon Solar Water Heaters During the System Application Phase

2004 ◽  
Vol 126 (3) ◽  
pp. 950-956 ◽  
Author(s):  
J. M. Chang
Keyword(s):  
Removal Efficiency ◽  
Empirical Model ◽  
System Application ◽  
Heat Removal ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Heat Removal Efficiency ◽  
Solar Water Heaters

The overall performance rating of a thermosyphon solar water heater should take into consideration its heat removal efficiency during the system application phase. This study employs a precise on-line operation to first identify physical heat removal patterns of a thermosyphon solar water heater, and then develops an empirical model for deriving its characteristic heat removal efficiency. This empirical model is in the form of a logarithmic curve, and has a high data correlation coefficient of 0.889 to 0.967. Based upon the empirical model, this study defines a characteristic heat removal efficiency parameter for thermosyphon solar water heaters. Finally, this study establishes a storage tank design method which enables the characteristic heat removal efficiency of the complete system to be optimized.

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