ABSTRACT
Ventilation improves indoor air quality and reduces airborne infections. It is particularly important at present because of the COVID-19 pandemic. Commercially available ventilation facilities can only be instantly turned on/off or at a set time with adjustable air volumes (high, middle, and low). However, maintaining the indoor carbon dioxide concentration while reducing the energy consumption of these facilities is challenging. Hence, this study developed clustering algorithms to determine the carbon dioxide concentration limit thus enabling real-time air volume adjustment. These limit values were set using the existing energy recovery ventilation (ERV) controller. In the experiment, dual estimation was adopted, and the constructing building energy models from data were sampled at a low rate to compare that the ventilation facilities are only turned on/off. In addition, switching control is closely related to fuzzy control;that is, fuzzy control can be considered a smooth version of switching control. The experimental results indicated that the limits of 600 and 700 ppm were suitable to effectively control the real-time air volume based on the ERV operation. An ERV-based carbon dioxide concentration limit reduced the energy consumption of ventilation facilities by 11%implications of this study. IEEE
ABSTRACT
With increasing energy use and outbreaks of respiratory infectious diseases (such as COVID-19) in buildings, there is a growing interest in creating healthy and energy-efficient indoor environments. A novel heating system named low-temperature radiant floor coupled with intermittent stratum ventilation (LTR-ISV) is proposed in this study. Thermal performance, indoor air quality, energy and exergy performance were investigated and compared with conventional radiant floor heating (CRFH) and conventional radiant floor heating with mixing ventilation (CRFH + MV). The results indicated that LTR-ISV had a more uniform operative temperature distribution and overall thermal sensation, and air mixing was enhanced without generating additional draft sensation. Compared with CRFH and CRFH + MV, the indoor CO2 concentration in LTR-ISV can be reduced by 1355 ppm and 400 ppm, respectively. Airborne transmission risk can also be reduced by 5.35 times. The coefficient of performance for CRFH, CRFH + MV, and LTR-ISV during working hours was 4.2, 2.5, and 3.4, respectively. The lower value of LTR-ISV was due to the high energy usage of the primary air handing unit. In the non-working hours, LTR-ISV was 0.6 and 1.3 higher compared to CRFH and CRFH + MV, respectively. The exergy efficiency of LTR-ISV, CRFH, and CRFH + MV was 81.77 %, 76.43 %, and 64.71 %, respectively. Therefore, the LTR-ISV system can meet the requirements of high indoor air quality and thermal comfort and provides a reference for the energy-saving use of low-grade energy in space heating.
ABSTRACT
Mobilized thermal energy storage (M−TES) is a promising technology to transport heat without the limitation of pipelines, therefore suitable for collecting distributed renewable or recovered resources. In particular, the M−TES can be flexibly used for the emergency heating in the COVID-19 era. Though the M−TES has been commercializing in China, there is not any specific regulation or standard for M−TES systems. Therefore, this paper summarizes and discusses the existing regulations and policies concerning M−TES in the aspects of facility manufacture and operation, road transportation, and financial support and guidance. Furthermore, the suggestions were presented including necessary consensus on the development of M−TES among different departments, consideration of local conditions when drafting or revising regulations and policies, sufficient investment, or subsidy on the R&D of M−TES, and qualification recognition of M−TES companies and staffs.
ABSTRACT
This paper focused on the impact of lifestyle changes in response to the novel coronavirus infection (COVID-19) on the electricity demand of 1339 detached houses from October 2020 to March 2021. Analyzing with the lifestyle questionnaire survey, twelve months after the first state of emergency for COVID-19 at April 2020, “working from home” was the only factor that increased household power consumption for 11% and the other factors were gone. Space heating power consumption in this period did not increase significantly. Lifestyle changes have affected household timely electricity demand and increased self-consumption of renewable energy of photovoltaic power generation systems.
ABSTRACT
The UK government has committed to reducing its carbon emissions to net-zero by 2050. Higher education institutions (HEIs) are high energy users, with the largest proportion of their energy demand for space heating;an area still dominated by carbon-intensive fuels. This research addresses the UK HEI space temperature policy landscape, making direct links between space temperature policy and carbon management, advocating the development of evidence-based policies as a critical tool for reducing carbon emissions within the sector. Sixty-six space temperature policies were reviewed, and five experienced energy managers were interviewed to understand the range, development and use of space temperature policies in UK HEIs. The research identified a lack of consistency across these policies, leading to missed opportunities for making energy and carbon savings. The research highlights gaps in the available data and literature needed to connect policy to its effectiveness, and identifies the use of policy as a defensive tool against complaints rather than an active driver of energy reduction. A series of recommendations are proposed for national and institutional policymakers, suggesting areas for improvement and future research to facilitate effective development and practice in space temperature policy towards net-zero.
ABSTRACT
In a vicious cycle, the rise of global temperatures increases demand for cooler indoor temperatures, while increased use of air conditioning leads to warmer outdoor temperatures. Most modern indoor-climate control systems aim to maintain thermal neutrality i.e., a near-constant indoor temperature, over entire spaces, if not also over time. This consumes significant resources while causing thermal discomfort for some indoor occupants. In an online study, this work explored user perceptions towards dynamic indoor temperatures, which can lead to significant resource conservation. The study included two conditions, early versus late exposure to a range-based thermostat, to assess its user acceptance, in the context of study participants' 1) summer temperatures, 2) general temperature preferences and habits, 3) temperature-unit preference, and 4) extra-thermal factors. Due to local COVID-19 restrictions on in-person research, initial results will report on users' behavioral intention. © 2022 Elsevier B.V.. All rights reserved.
ABSTRACT
Several contrasting effects are reported in the existing literature concerning the impact assessment of the COVID-19 outbreak on the use of energy in buildings. Following an in-depth literature review, we here propose a GIS-based approach, based on pre-pandemic, partial, and full lockdown scenarios, using a bottom-up engineering model to quantify these impacts. The model has been verified against measured energy data from a total number of 451 buildings in three urban neighborhoods in the Canton of Geneva, Switzerland. The accuracy of the engineering model in predicting the energy demand has been improved by 10%, in terms of the mean absolute percentage error, as a result of adopting a data-driven correction with a random forest algorithm. The obtained results show that the energy demand for space heating and cooling tended to increase by 8% and 17%, respectively, during the partial lockdown, while these numbers rose to 13% and 28% in the case of the full lockdown. The study also reveals that the introduced detailed occupancy scenarios are the key to improving the accuracy of urban building energy models (UBEMs). Finally, it is shown that the proposed GIS-based approach can be used to mitigate the expected impacts of any possible future pandemic in urban neighborhoods.
ABSTRACT
Trombe wall is a simple and mature passive solar building design while its utilization of solar energy is limited to space heating. Aerosol transmission, as a potential transmission pathway of COVID-19, poses a serious threat to the public health especially in a closed indoor environment. The thermal disinfection of virus, which can be easily integrated into solar systems, seems to be a suitable method for controlling bioaerosols. Therefore, a novel disinfected Trombe wall for virus inactivation and space heating is proposed, providing a potential way to fight the current COVID-19 pandemic. After the proposal of the concept, its performance on space heating and virus inactivation was investigated through experimental and simulation methods. The main results were as follows: (1) The average thermal efficiency was 0.457 and the average indoor temperature was 20.7 â, 1.9 â higher than the ambient temperature. (2) The maximum single-pass inactivation ratio was 0.893, 0.591 and 0.893 while the total production of clean air was 112.3, 63.8 and 114.7 m3 for SARS-CoV-1, SARS-CoV-2 and MERS-CoV, respectively. (3) The increase of ambient temperature or solar irradiance may enhance the thermal efficiency while the former has little effect on the thermal disinfection process. (4) Extending the height or narrowing the thickness of the duct by 40% may contribute to an increase in total production of clean air by 510 m3 or 681 m3 per unit area during the heating seasons, but the later may cause a larger decrease (about 8%) in the heat gain of indoor air.