Conventional Electric Water Heaters Research Articles

Design and Development of a Solar-Powered Smart Heater

Renewable energy sources are those that replenish naturally without depletion. Example of such sources are bioenergy, hydropower, geothermal, wind and solar energy sources. The alarming rate of global energy demand and consumption necessitates an immediate solution for energy conservation and maximum efficiency of new technological gadgets now being built. As a gadget, a solar water heater transforms dc electricity into heat energy, which is then transferred to the water in which it is immersed. The size of the heater is determined by its design, capacity, and intended purpose; it might be for household or industrial use. As an alternative to conventional electric water heaters, this effort focuses on the design and development of a solar-powered smart water heater. In tests using a variety of settings, the solar-powered smart heater that was constructed performed admirably. The components used include a PIC16F876A microcontroller, a 12 V/300 W monocrystalline PV, a 12 V/ 40 A charge controller, and 12 V / 150 W dc submersible heating element among others The temperature control capacity of the fabrication makes it useful in water management system applications such as in aquaculture fingerling hatchery, hot water dispenser and shower among others. The system showed excellent performance in water temperature control using a 150 watts dc heater. Keywords:Solar, heater, photo-voltaic, temperature-controlled, direct current, alternating current .

Cradle-to-grave life cycle assessment of an air to water heat pump: Case study for the Lebanese context and comparison with solar and conventional electric water heaters for residential application

This study investigates the environmental performance of the air source heat pump (ASHP) technology. The life cycle assessment (LCA) methodology is used. An LCA analysis provides a clear understanding of the environmental impacts of a product throughout its life cycle. This paper aims to i) determine and analyze the environmental impacts of the ASHP and ii) compare the impacts of the ASHP with those associated with a flat plate (FP) solar water heater (SWH) and a conventional electric water heater (CEWH). The functional unit is “heating 416,100 L of water to 60 °C”. The software used is SimaPro and the impact assessment method is IMPACT 2002+. Results show that the copper pipes of the ASHP are the highest contributors to 6 out of 15 impact categories for the assembly. Moreover, the refrigerant inside the pump is the highest contributor to ozone layer depletion (90.25%). The life cycle results of the three systems show a large contribution of the use phase to the total life cycle impacts. This leads to a need for improving the refrigerant, the Lebanese electricity grid and if possible changing the material of the heat pump pipes. The comparative LCA proves that the ASHP is the best alternative due to its low power requirement during the use phase: Lebanese households could save 1668.45 kg CO2eq and 16983.25 kg CO2eq by installing an ASHP instead of the solar water heater and the electric water heater, respectively. This work encourages installations of this better alternative across Lebanon's residential sector and in the world in order to mitigate the harm to the environment and further improve the use of renewable energy.

Solar driven water heating systems for medium-rise residential buildings in urban mediterranean areas

International Energy Agency reported that buildings are accountable for one-third of the global final energy demand in 2017. On-site renewable energy generation can reduce buildings' grid electricity consumptions. Medium-rise buildings located in urban areas have limited available rooftop or facade surfaces, thus solar driven technologies such as solar thermal, photovoltaics (PV) or photovoltaics/thermal (PV/T) are in competition for the available space. This investigation aims to compare available solar driven water heating systems in the market, suitable to replace the conventional electric water heater for a multi-residential building. Under the present study, solar PV electric water heating system (S1), solar thermal water heating system with electric boosting (S2), solar PV/T water heating system with electric boosting (S3) and integrated solar PV and heat pump water heating system (S4) are investigated. The performance parameters compared are the annual net electricity consumption from the grid and the net present value of life-cycle cost (LCC) for 20 years life. Results reveal that S3 and S4 have ‘net’ positive electricity production but higher initial costs, compared to the other systems. For buildings located in colder climates, S2 has lower LCC compared to S3 but for warmer climates the LCC of S3 is the lowest.

Experimental and simulation studies on air source heat pump water heater for year-round applications in Canada

The performance of a new type of Air Source Heat Pump Water Heater (ASHPWH) has been investigated. ASHPWH has a better performance than the conventional electric water heater if it is installed in a hotter climate. However, the conditions are different in Canada, where outside air temperature is well below the freezing point for several months, and that diminishes the water heating capacity of these systems significantly. On the other hand, if it is installed in the indoor space (which is the case of this research), the presence of the system in the house affects the house heating and cooling loads. Therefore, an understanding of energy performance of this types water heaters is critical to justify their use in the Canadian houses. The research methodology involved, installation of the ASHPWH unit in an Archetype Sustainable House (ASH), reconfiguration of some parts of house plumbing system, build sensors and data acquisition system to collect real-time experimental data, developed and validated TRNSYS models. Furthermore, the validated models were applied to evaluate the performance of the unit to meet the year-round hot water demand and established its significance with respect to the conventional electric water heater. It was concluded that the temperature and humidity of surrounding air produced a considerable impact on the heating capacity of the ASHPWH. The best coefficient of performance (COP) was obtained at 20 °C and 35% RH from the chosen sets of air conditions. The outlet water temperature fluctuates in the range of 49.5 °C to 55.9 °C (while the setpoint temperature was taken at 54 °C). The system will increase the combined space heating and cooling electricity consumptions annually by 3%, on the other hand, a reduction of 55% of water heater related annual electricity consumption was noted relative to the conventional electric water heater.

Air source heat pump water heater: Dynamic modeling, optimal energy management and mini-tubes condensers

This paper presents a dynamic simulation model to predict the performance of an ASHPWH (air source heat pump water heater). The developed model is used to assess its performance in the Lebanese context. It is shown that for the four Lebanese climatic zones, the expected monthly values of the average COP (coefficient of performance) varies from 2.9 to 5, leading to high efficiencies compared with conventional electric water heaters. The energy savings and GHG (greenhouse gas) emissions reduction are investigated for each zone. Furthermore, it is recommended to use the ASHPWH during the period of highest daily ambient temperatures (noon or afternoon), assuming that the electricity tariff and hot water loads are constant. In addition, an optimal management model for the ASHPWH is developed and applied for a typical winter day of Beirut. Moreover, the developed dynamic model of ASHPWH is used to compare the performance of three similar systems that differ only with the condenser geometry, where results show that using mini-condenser geometries increase the COP (coefficient of performance) and consequently, more energy is saved as well as more GHG emissions are reduced. In addition, the condenser “surface compactness” is increased giving rise to an efficient compact heat exchanger.

Calibrated simulation of a solar hot water system to match degraded performance over a 22-year period using two models

This paper reports on the measured performance of a residential solar water heating system over a period of 22 years and the modeling of the system to simulate its degradation over that period. The system consists of three fixed flat-plate collectors with a total of 5 m 2 of double-layer glass cover plates and black aluminum fin-tube absorber plates. The solar storage tank capacity is 303 L, which is used as a pre-heater to a 114-L conventional electric water heater. Measurements and simulations indicate that fogging of the glass cover plates has reduced the transmissivity by around 63% over the 22 years.

Development of Thermoelectric Heat Pump Water Heaters

Experiments verified that a thermoelectric heat pump system is more efficient than an electrical heating device, for its heating coefficient reached more than 1.6 with suitable operating conditions. Two novel instantaneous water heaters were developed and tested successively. The prototype with circulating water pump can save power consumption more than 40% in comparison with conventional electric water heaters, while the prototype integrating with thermosiphon can save more than 38%. Comparing two prototypes, the latter prototype becomes more compact, more technologically advanced and practical, because it eliminated the working life choke-point of the former, while holding the advantages, such as high efficiency, reliability, safety, environmental friendly.

A novel water heater integrating thermoelectric heat pump with separating thermosiphon

Experiments verified that a thermoelectric heat pump system is more efficient than an electrical heating device, for its heating coefficient reached more than 1.6 with suitable operating conditions. On the base of experimental data, a novel instantaneous water heater was developed by means of integrating thermoelectric (TE) heat pump with separating thermosiphon. The original flow path of the prototype facilitated heat recovering from drainage, and remarkably reduced the temperature difference between heat sink and source of the TE heat pump, thus its performance is improved greatly. Performance tests illustrated that the prototype can save more than 38% of the power consumption compared with that of conventional electric water heaters. It is of great practical interest in building energy saving, supplying hot water for carriages, ships and other analogous movable spaces.

Financing solar thermal technologies under DSM programs: an innovative approach to promote renewable energy

A wide range of demand side management (DSM) options has been practiced so far in developed as well as in developing countries. However, solar thermal technologies have been left out from DSM programs considering them as supply side options. This study argues that a number of solar thermal technologies, which provide the same services as electric appliances, can be considered as DSM options and examines the possibility of promoting solar water heaters (SWH) under DSM programs in Thailand. The study found that installation of SWH in place of conventional electric water heaters (EWH) to meet hot water demand in the residential sector would be economically beneficial to the country as a whole. However, switching to SWH from EWH would be unlikely without having government interventions as there would be no incentives to individual consumers in doing so. If the government or state electric utilities provide funding to residential consumers through DSM programs for replacing their EWH by SWH, the total electricity generation in Thailand during the 2000–2015 period would decrease by 3.8 per cent. Moreover, promotion of SWH under DSM programs would cause 3.35 and 1.41 per cent reductions of total power sector CO2- and NOx-emissions respectively, during the same period. This study also reveals that solar thermal technologies, especially the SWH, could be better options for DSM programs compared to the end-use efficiency improvement options in Thailand. Copyright © 2000 John Wiley & Sons, Ltd.