scholarly journals How much energy can optimal control of domestic water heating save?

2019 ◽  
Author(s):  
MJ Booysen ◽  
J.A.A. Engelbrecht ◽  
Michael Ritchie ◽  
Mark Apperley ◽  
Andrew Cloete
Keyword(s):  
Optimal Control ◽  
Fossil Fuels ◽  
Energy Use ◽  
Hot Water ◽  
Water Usage ◽  
Water Heating ◽  
Domestic Water ◽  
Water Heaters ◽  
Point Of Use ◽  
The Impact

Scheduled control of domestic electric water heaters, designed to cut energy use while minimising the impact on users' comfort and convenience, has been fairly common for some time in a number of countries. The aim is usually load-shifting (by heating water at off-peak times) and/or maximising time-of-use pricing benefits for users. The scheduling tends not to be linked to actual hot water usage and depends largely on stored thermal energy. Heat losses therefore tend to be greater than if the heater ran without a break. The effect of such a control strategy is thus to worsen the energy loss and in most cases increase greenhouse gas emissions. Many developing countries have flat-pricing (no time-of-use incentives) and rely heavily on energy from fossil fuels, making these considerations even more pressing. We explore three strategies for optimal control of domestic water heating that do not use thermostat control: matching the delivery temperature in the hot water, matching the energy delivered in the hot water, and a variation of the second strategy which provides for Legionella sterilisation. For each of these strategies we examine the energy used in heating, the energy delivered at the tank outlet, and issues of convenience to the user. The study differs from most previous work in that it uses real daily hot-water usage profiles, ensures like-for-like comparison in delivered energy at the point of use, and includes a daily Legionella avoidance strategy. We tackled this as an optimal control problem using dynamic programming. Our results demonstrate a median energy saving of between 8\ and 18% for the three strategies. Even more savings would be realised if intended and unintended usage events are correctly classified, and the optimal control only plans for intended usage events.

scholarly journals Practically-Achievable Energy Savings with the Optimal Control of Stratified Water Heaters with Predicted Usage

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1963
Author(s):  
Michael J. Ritchie ◽  
Jacobus A.A. Engelbrecht ◽  
Marthinus J. Booysen
Keyword(s):  
Optimal Control ◽  
Fossil Fuels ◽  
Energy Savings ◽  
Electrical Energy ◽  
Hot Water ◽  
Prediction Errors ◽  
Water Usage ◽  
Energy Usage ◽  
Water Heaters ◽  
The Ideal

Residential water heaters use a substantial amount of electrical energy and contribute to 25% of the energy usage in the residential sector. This raises concern for users in countries with flat rate electricity fees and where fossil fuels are used for electricity generation. Demand side management of tanked water heaters is well suited for energy-focused load reduction strategies. We propose a strategy for providing an electric water heater (EWH) with the optimal temperature planning to reduce the overall electrical energy usage while satisfying the comfort of the user. A probabilistic hot water usage model is used to predict the hot water usage behaviour for the A*-based optimisation algorithm, which accounts for water stratification in the tank. A temperature feedback controller with novel temperature and energy-correcting capabilities provides robustness to prediction errors. Three optimal control strategies are presented and compared to a baseline strategy with the thermostat always on: The first ensures temperature-matched water usages, the second ensures energy-matched water usages, and the third is a variation of the second that provides Legionella prevention. Results were obtained for 77 water heaters, each one simulated for four weeks. The median energy savings for predicted usage were 2.2% for the temperature-matched strategy, and 9.6% for both of the energy-matched strategies. We also compare the practical energy savings to the ideal scenario where the optimal scheduling has perfect foreknowledge of hot water usages, and the temperature and energy-matched strategies had a 4.1 and 11.0 percentage point decrease from the ideal energy savings.

Residential Water Heating Dehumidifier (WHD) With Devoted Dehumidification

2005 ◽  
Author(s):  
Aaron K. Ball ◽  
Chip W. Ferguson ◽  
Frank T. Miceli ◽  
Evelyn Baskin
Keyword(s):  
Heat Pump ◽  
Energy Use ◽  
Hot Water ◽  
Maximum Efficiency ◽  
Electric Resistance ◽  
Water Heating ◽  
Water Heater ◽  
Water Heaters ◽  
Heat Pump Water Heater ◽  
Residential Water

A new a dual-service dehumidifier water heater (WHD) appliance is being researched and developed by the authors. Prior research on a similar appliance, a heat pump water heater (HPWH), has demonstrated the unit’s increased performance and energy saving, and through collaboration, significant progress has been made toward developing the WHD into a potentially marketable product. The primary energy use in residential households is space conditioning (49%), and the second major energy use is hot water consumption. In DOE’s 2004 Buildings Data Book, 15.5 percent of residential energy utilization is consumed by water heating (DOE 2004, Table 1.2.3). The two major types of residential water heaters are direct gas fired (~55%) and electric resistance (~45%) (DOE 2004, Appliance Magazine 2005). The maximum efficiency of a standard electric resistance water heater is 1 (100%), and progress has been made to increase the efficiency of the current standard heaters to approximately 95 percent (DOE 2004, Table 5.10.6), which is roughly the maximum available with today’s technology. However, if the standard system is replaced by a Heat Pump Water Heater (HPWH), the performance can be increased by 140 percent (Zogg and Murphy 2004). The WHD operates as a HPWH while heating water and as a dedicated dehumidifier when water heating is not necessary. This paper presents the general design and laboratory testing results of a WHD. Preliminary performance data reveal coefficient of performances (COP) of approximately 2.2 during water heating. Further, market analysis has revealed that a potential need for this new technology is in regions with high humidity (Ashdown et al. 2004). These regions are primarily in the Northeast, Southeast and some coastal areas of the U.S. Current HPWH units do not have dedicated dehumidification and have a very small share of the residential water heat market. Of the 9.55 million residential water heaters sold in 2003 only about 2,000 of them were HPWHs (DOE 2004, Table 5.10.15).

scholarly journals The Impact of Lack of Clean Cooking Fuels on Sustainable Development in Developing Countries

2018 ◽  
Author(s):  
Ifeoluwa Garba ◽  
Richard Bellingham
Keyword(s):  
Sustainable Development ◽  
Developing Countries ◽  
Fossil Fuels ◽  
Energy Use ◽  
Business Models ◽  
Clean Energy ◽  
Well Being ◽  
The World ◽  
Cooking Fuels ◽  
The Impact

Access to energy is crucial in tackling many of the current global development challenges that impact on people’s economic, health and social well-being as well as the ability to meet the commitments of reducing carbon emissions through clean energy use. Despite increased attention from multiple governments and agencies, energy poverty remains a serious sustainable development issue in many developing countries. To date, most research have focused on general access to electricity and the generation of clean energy to replace fossil fuels, failing to address the lack of basic access to clean energy for cooking and heating. More people in the world lack access to clean cooking fuels than to electricity. This issue is one aspect of a broader research which investigates the impacts of optimized energy policy and energy business models on sustainable development in developing countries.

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.

Predictive Model and Application of a Hybrid GSHP System for Space Conditioning, Water Heating and Deicing of a Seniors Independent Living Center

2004 ◽  
Author(s):  
Joseph R. Wrobel
Keyword(s):  
System Design ◽  
Energy Use ◽  
Operating Experience ◽  
Solution Space ◽  
Estimation Algorithm ◽  
Parametric Estimation ◽  
Working Fluid ◽  
Water Heating ◽  
Domestic Water ◽  
Magnitude Scaling

A parametric estimation algorithm is described for system design criteria selection in Ground Source Heat Pump (GSHP) Heating, Ventilation and Air Conditioning (HVAC) applications requiring dissipation of annual cycle excess thermal energy to the air, i.e., a hybrid mode. The model applies a combination of order-of-magnitude scaling (OMS) and classical non-dimensional flow and heat transfer methods. The objective is to develop a simplified parametric range display for selection of design values. Application requirements and constraints map into the solution space for specific design value selections. The annual thermal budget cycle is configured to time-phase the earth-stored excess energy from the cooling season for dissipation in the heating season using water to ambient forced-air (fan-coil) cooling. Estimators for an application are developed for the quantity, spacing and depth of well bores and the loop flow rate range based on Reynolds number and Nusselt number correlations for water and earth thermal properties. A case study application in two parts is described. The GSHP system uses a common working fluid (water) in a closed loop serving all 70 zones to furnish heating, cooling, domestic water heating, and exterior walkway deicing for an 80,000 sq. ft. area, 54 apartment, senior, center in Dallas Texas, USA. In 1999, the initial Phase I facility of 55,000 sq. ft. area was occupied using the full capacity flow system design without the dissipation coolers. In 2004 the coolers were included with the expansion to full occupancy. Design parameter values, operating experience, energy use, and the rationale for the demonstrated compatibility of the single solution for essentially two applications are described.

scholarly journals Impact of Electric Vehicle Charging Strategy on the Long-Term Planning of an Isolated Microgrid

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3455
Author(s):  
Jean-Michel Clairand ◽  
Carlos Álvarez-Bel ◽  
Javier Rodríguez-García ◽  
Guillermo Escrivá-Escrivá
Keyword(s):  
Renewable Energy ◽  
Fossil Fuels ◽  
Energy Use ◽  
Environmental Benefits ◽  
Electric Vehicle Charging ◽  
Power Generation Planning ◽  
Smart Charging ◽  
The Impact ◽  
Ev Charging ◽  
Charging Strategy

Isolated microgrids, such as islands, rely on fossil fuels for electricity generation and include vehicle fleets, which poses significant environmental challenges. To address this, distributed energy resources based on renewable energy and electric vehicles (EVs) have been deployed in several places. However, they present operational and planning concerns. Hence, the aim of this paper is to propose a two-level microgrid problem. The first problem considers an EV charging strategy that minimizes charging costs and maximizes the renewable energy use. The second level evaluates the impact of this charging strategy on the power generation planning of Santa Cruz Island, Galapagos, Ecuador. This planning model is simulated in HOMER Energy. The results demonstrate the economic and environmental benefits of investing in additional photovoltaic (PV) generation and in the EV charging strategy. Investing in PV and smart charging for EVs could reduce the N P C by 13.58%, but a reduction in the N P C of the EV charging strategy would result in up to 3.12%.

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.

A Rating Procedure for Solar Domestic Water Heating Systems

1983 ◽  
Vol 105 (4) ◽  
pp. 430-439 ◽  
Author(s):  
S. A. Klein ◽  
A. H. Fanney
Keyword(s):  
Heating System ◽  
Testing Procedure ◽  
Hot Water ◽  
National Bureau ◽  
Water Heating ◽  
Domestic Water ◽  
Solar Water Heating System ◽  
Long Term Performance ◽  
Term Performance

A rating procedure for solar domestic hot water systems is described which combines the advantages of short-term system tests and correlations of long-term thermal performance. The testing procedure consists of two indoor tests which are in accordance with ASHRAE Standard 95-1981, except for one additional measurement needed only for systems employing a heat exchanger between the collector fluid and the potable water. The test results are plotted in a manner in which they can be used to estimate the long-term performance of the solar water heating system for any location where site-specific, monthly-average meterological data are available. The annual solar function obtained in this manner provides the recommended rating indicator. The validity of this rating procedure is first demonstrated by simulations. Further support is provided by experiments conducted at the National Bureau of Standards.

scholarly journals Non-Invasive Estimation of Domestic Hot Water Usage with Temperature and Vibration Sensors

2019 ◽  
Author(s):  
MJ Booysen
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Water Consumption ◽  
Flow Measurement ◽  
Hot Water ◽  
Water Usage ◽  
Flow Rates ◽  
Domestic Hot Water ◽  
Non Invasive ◽  
Water Heaters

Electric water heaters are responsible for a large portion of electricity consumption and water usage in the domestic sector. Smart water heaters alleviate the strain on the electricity supply grid and reduce water consumption through behavioural change, but the installation of in-line flow meters is inconvenient and expensive. A non-invasive water flow meter is proposed as an alternative. Non-invasive flow measurement is more common for high flow rates in the industrial sector than for domestic applications. Various non-invasive water measurement methods are investigated in the context of domestic hot water, and a combination of thermal- and vibration-sensing is proposed. The proposed solution uses inexpensive, easily installable, non-invasive sensors and a novel algorithm to provide the same flow measurement accuracy as existing in-line meters. The algorithm detects the beginning and end of water consumption events with an accuracy of 95.6%. Quantitative flow rate estimation was possible for flow rates greater than 5 L min⁻¹ with an accuracy of 89%, while volumetric usage estimation had an accuracy of more than 93%. The algorithm limitations were applied to field data, revealing that water consumption could be detected with an error of less than 12% within the limitations of the proposed algorithm. The paper presents a successful proof of concept for a non-invasive alternative to domestic hot water flow rate measurement.

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