Transient and Rate-Dependent Performance of Conventional Electric Storage Water Heating Systems

2005 ◽  
Vol 128 (1) ◽  
pp. 90-97 ◽  
Author(s):  
J. W. McMenamy ◽  
K. O. Homan
Keyword(s):  
Electrical Power ◽  
Performance Limits ◽  
Water Heating ◽  
Water Heater ◽  
Storage Element ◽  
Heating Systems ◽  
Water Heaters ◽  
Rate Dependent ◽  
Power Draw ◽  
Storage Volume

Electric resistance water heaters are relatively simple and are therefore one of the most common water heating configurations. Due to constraints on the allowable instantaneous electrical power draw, most electric water heating systems incorporate a sizable thermal storage component. The inherently unsteady storage component therefore has an overwhelming impact on the system behavior. In this investigation, a residential-scale electric storage water heater was tested across a range of flow rates for both powered and nonpowered discharge processes as well as for charge processes with no throughflow. The flow dynamics internal to the storage volume is shown to be strongly multidimensional and transient, especially when the internal heating elements are energized. Comparison of the measured data to the performance limits of a system with a fully mixed or a perfectly stratified storage element reveals that the conventional system operates relatively near to the fully mixed limit. As a result, there appears to be significant potential for improvements in system performance through reductions in the level of thermal mixing internal to the storage volume.

Thermodynamic Optimization of Electric Water Heating With Fully-Mixed Storage: First Law Efficiency

2001 ◽  
Author(s):  
K. O. Homan
Keyword(s):  
Discharge Rate ◽  
Minimum Energy ◽  
Electric Heating ◽  
High Energy ◽  
Significant Loss ◽  
Water Heating ◽  
Water Heater ◽  
Loss Mechanism ◽  
Water Heaters ◽  
Storage Volume

Abstract The energy consumed for water heating is a significant fraction of the total national use. The most common water heater design, particularly at the residential level, incorporates thermal storage capacity to accommodate the typically high energy withdrawal rates. For electric water heaters, the only significant loss mechanism is ambient heat exchange. In the present paper, three different configurations consisting of a fully-mixed storage vessel and an electric heating element are analyzed. Compared on the basis of equal performance, defined as a sustained draw at or above a minimum energy discharge rate, the configurations are shown to require significantly different storage volumes for identical energy input rates. Accounting for ambient heat loss, these differences in storage volume are shown to translate into appreciably higher thermal efficiencies for the configuration with the smallest required storage volume.

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.

Solar Water Heaters: A Review of Systems Research and Design Innovation

Green ◽  
2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Brian Norton
Keyword(s):  
System Development ◽  
Unit Cost ◽  
Hot Water ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water Heating ◽  
Solar Water ◽  
Water Heaters ◽  
Systems Research ◽  
And Performance

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.

Study of Different Types of Water Heating Systems - Under Living Lab Conditions

2019 ◽  
Author(s):  
Swapnil Dubey
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Heating System ◽  
Heat Pumps ◽  
Electrical Heating ◽  
Water Heating ◽  
Water Heater ◽  
Water Heaters ◽  
Living Lab ◽  
Almost All

Abstract In Singapore, roughly 20% of the energy consumed by households is used for water heating and almost all the energy consumed by conventional electric water heaters. One of the significant potential energy saving opportunities lies in using energy-efficient water heating appliances. Recently, there has been a move towards energy-saving design and the use of natural refrigerants over fluorocarbons. Unlike conventional electric storage water heaters, which use electricity to heat water directly, heat pump storage water heaters use electricity only to operate a pump that circulates refrigerants around the system. This refrigerant collects heat from the surrounding atmosphere and transfers it to the water. CO2 heat pumps have low global warming potential when compared to other refrigerants based heat pumps, has zero ozone depletion potential, inexpensive, non-flammable, generate high temperature. In this project, a comparative analysis of three different water heater types has been presented based on real-time usage and living-lab conditions under the tropical climate of Singapore. These three types are: 1. Electrical heater storage type 2. Hybrid heat pump with auxiliary electrical heating water heater 3. CO2 heat pump water heater without auxiliary heating Study found significant energy saving using CO2 heat pump compared to other water heating system and also better for environment.

System Performance of an Indirect Collector Storage Preheater in Series With a Conventional Electric Resistance Water Heater

Solar Energy ◽  
2005 ◽  
Author(s):  
A. M. Boies ◽  
K. O. Homan
Keyword(s):  
Thermal Performance ◽  
System Performance ◽  
Low Cost ◽  
Electric Resistance ◽  
Water Heating ◽  
Water Heater ◽  
Domestic Water ◽  
Solar Fraction ◽  
Storage Volume ◽  
In Series

Solar integral collector storage (ICS) devices are a potentially low cost means of displacing a portion of the energy required for domestic water heating. However, since ICS systems are rarely used as a stand-alone system and are more typically utilized as a preheater for conventional water heaters, it is imperative to analyze the overall water heating system in order to determine the advantage of any improvements in the thermal performance of the ICS component. In particular, this paper analyzes the performance of a solar ICS heater, in divided and undivided storage configurations, in series with a conventional electric resistance water heater (ERWH) for a range of ICS storage volumes, heat exchanger NTU, initial ICS temperature, and ERWH storage volumes. The undivided storage configuration corresponds to the typical UPICS system whereas the divided storage configuration corresponds to a recently proposed concept for improving the thermal performance of the ICS device. The results show that the ICS preheater does provide significant increases in solar fraction when adequately sized. Although comparison of the divided to undivided storage concept, with the same total ICS storage volume, shows only modest gains of 5–10% in solar fraction, the ICS storage volume necessary to attain the same solar fraction is much less for the divided storage concept. The smaller required storage volume would, in turn, enable faster charging times and potentially higher initial temperatures thereby leading to even further improvements in overall system performance.

DOSED-CAPACITY ELECTRODE WATER HEATER USED IN BOILING AND HEATING INSTALLATIONS

2021 ◽  
pp. 72-75
Author(s):  
LEONID P. SHICHKOV ◽  
Keyword(s):  
Energy Transfer ◽  
Single Phase ◽  
Operation Mode ◽  
Heating System ◽  
Electrical Circuit ◽  
Heating Power ◽  
Electrical Safety ◽  
Water Heating ◽  
Water Heater ◽  
Water Heaters

Power change of electrode water heaters depending on the water quality is their main disadvantage. To eliminate this drawback and improve the reliability of water heaters, an electrode water heating system was developed and its operating mode was analyzed. The paper considers an aggregated system of electric water heating, consisting of a single-phase electrode water heater connected to a single-phase network via a valve-capacitor converter with a metered energy transfer. To regulate and stabilize the heating power, the storage capacity of the converter is divided into separate sections. The performed formula analysis of the load mode of the aggregated system allows optimizing its operation mode. In order to increase the safety and ease of operation of the installation, additional interlocks of the corresponding electrical circuits are provided in the electrical circuit. The authors conclude that it is advisable to use single-phase electrode water heaters by switching on through a valve-condenser converter with dosed energy transfer, which allows regulating and stabilizing the heating power and thereby increasing electrical safety, functionality, reliability of electrode water heaters, as well as ensuring a signifi cant improvement in the quality of operation.

scholarly journals Comparative Analysis of Exergy and Efficiency for Stratified Thermal Storage Tank with Solar Flat Plate and Evacuated Tube Collectors

2016 ◽  
Vol 855 ◽  
pp. 114-118 ◽  
Author(s):  
Sukruedee Sukchai ◽  
Yodthong Mensin ◽  
Wikarn Wansungnern
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Water Heating ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Evacuated Tube Solar Collector ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

In recent years, solar water heating technology has got the major importance in water heating applications. For the efficient and effective working of solar water heaters, storage of the hot water is the main issue in this water heating technologies. This paper mainly presents the exergy and efficiency comparison between the solar flat plate water heater and evacuated tube water heater. A five level stratified thermal storage tank is designed and developed for this analysis. At each level of the tank, temperature of the water is collected for each one hour interval from 9:00 to 16:00 hours in both cases and the overall exergy and efficiency of the two water heaters were calculated. The average efficiency of all the levels for flat plate and evacuated tube collectors are 7.91% and 8.20% respectively. The overall system efficiency is obtained as 39.54% for flat plate and 41.00% for evacuated tube solar collector. At each level exergy is calculate for both systems and the average exergy of all the levels for flat plate collector is 4.243 kW and for evacuated tube solar collector is 4.371 kW.

Evaluation of Solar Water Heating Systems in Botswana

2013 ◽  
Vol 824 ◽  
pp. 459-466
Author(s):  
M.T. Oladiran ◽  
E. Ossenburg
Keyword(s):  
System Design ◽  
Payback Period ◽  
Local Market ◽  
Solar Water Heater ◽  
Water Heating ◽  
Water Heater ◽  
Heating Systems ◽  
Solar Water Heating ◽  
Solar Water ◽  
Suitable System

This paper presents results of an assessment of several solar water units to determine causes of their malfunctioning. A survey of solar water heater (SWH) installations in the Gaborone area, Botswana was carried out to obtain performance characteristics of SWH in the local market. Extensive inspections were performed on both in-service and non-functioning units, problems were diagnosed and pragmatic solutions were proffered. The paper presents some of the discoveries made during the investigation, namely, several units did not last up to the payback period of say 10 to 15 years. The results obtained could provide guidance in selecting operating criteria and suitable system design for solar water heating applications.

Sign in / Sign up

Export Citation Format

Share Document