11 - Energy Conversion Systems

Towards modern options of energy conservation in buildings

Towards wearable thermal comfort assessment framework by analysis of heart rate variability

In recent years, the momentum around green hydrogen is rising. Ambitious plans and roadmaps have been set to enable the massive development of green hydrogen as a mean for decarbonization. For that purpose, a huge focus is being made on currently available water electrolysis technologies which enable to produce green hydrogen as long as they are fed with renewable electricity.Working on the electrolyzer energy losses, efficiency can be maximized through smart thermal systems designed to valorize waste heat for use in district thermal systems. Conceptual studies have been proposed in relation with the waste heat recovery from electrolysis plants, however, there are no extensive reports examining the synergies between hydrogen production hubs and thermal energy valorization in end-use applications at district scale.To address this gap, this paper aimed to examine how excess heat generated by electrolysis plants can be utilized by thermal energy networks for serving end-use applications such as space heating and domestic hot water heating. The integration potential was evaluated as well as the necessity of heat upgrading technology bricks.

Potential for energy conservation in apartment buildings

Assessment of energy and natural resources conservation in office buildings using TOBUS

This review paper focuses on documenting and studying published papers and works in the field of solar heating and cooling air space in residential buildings. The goal of this survey and documentation is to find out the most important flushing results and conclusions specifically in the fields of using solar energy for space heating, cooling, and ventilation of local residential buildings in Libya. This covers using active and passive solar systems in, achieving thermal human comfort in such buildings leading to reduce electrical energy consumption. This paper also concentrates on applying energy efficiency measures in buildings; planning, design, and construction stages with the use of the principles of energy conservation in buildings. There are several studies comparing traditional with modern house designs in several local cities including both famous old cities of “Ghadames” and “Gharyan”. Several conclusions and recommendations are summarized within the text of this paper.

Increasing daily energy demand is a cause of concern globally; buildings consume most of the energy generated, so energy conservation in buildings should be a prime concern to save energy worldwide. In the Indian context, among the previous studies to figure out the driving factors responsible for conservation of energy in buildings, they focused mainly on a sector of buildings or highly localized, lacking a holistic approach. The attempt to find building conservation factors is meager and is in scarcity. This research fills the gap by providing a holistic approach to driving factors responsible for energy conservation in buildings. The present study seeks to explore the interrelationships between the twenty factors identified in this research using interpretive structural modeling (ISM) methodology. It arrives at the dominant factors that are highly influential in driving conservation principles in built environments in India. Among the twenty factors identified, the results indicate that the six most highly impactful factors are industry orientation, comfort, change in lifestyle, saving the environment, promoting sustainability, and testing new theories in energy conservation. The managerial applications of the derived results of this research are also discussed.

BLCC Quick Input (computer program) single compound amount (factor) savings-to-investment ratio simple payback single present value (factor) uniform present value (factor) UPV* modified uniform present value (factor) COURSE OBJECTIVES Know how to use economic analysis to improve capital investment decisions related to energy conservation in buildings Know the common methods and assumptions required for life-cycle cost analyses of energy-related investments in federal buildings Know how to use the BLCC program for life-cycle cost analysis IX COURSE OVERVIEW DAY ONE The course begins with a discussion of the types of economic decisions usually required by engineers, architects, and building managers concerned with improving the energy performance of buildings. An overview is given of how life-cycle costing and related methods of economic analysis can improve energy-related investment decisions. The elements of performing a life-cycle cost evaluation are explained.

Energy Conservation in Buildings – a Review

Chapter 564 - Cost-Benefit Analysis Approach for Energy Conservation in Buildings

In 2016, space heating (SH) and domestic hot water (DHW) heating for Canadian residential buildings accounted for 11% of Canada's total greenhouse gas (GHG) emissions. To drastically decrease the GHG emissions from the residential sector, solar thermal energy can be used to fulfill the SH and DHW needs of residential buildings. A major challenge for solar energy use in Canada is the timing mismatch between the solar radiation received and the SH needs of homes. A seasonal thermal energy store bridges this gap by storing thermal energy and discharging it when the demand arises. Sand can be used as the medium in thermal energy storage, but no research has yet been published demonstrating the feasibility or efficiency of a sand-based seasonal thermal energy store (SSTES) for a residential building. A full-scale research house with a solar combisystem and an SSTES has been built in Ottawa, Canada, to evaluate this novel technology. This thesis documents and analyzes a year-long experiment that was performed at the research house to assess whether the solar combisystem and SSTES can fulfill over 90% of the house’s annual SH and DHW heating needs with solar energy. It also presents the development of a 3D, conduction-only numerical model of the heat transfer in and around the SSTES that is validated with the data from the year-long experiment. Validated numerical models allow various design scenarios to be tested and optimized with less time and economic investment. The experimental results show that solar energy fulfilled 70% of the house’s annual SH and DHW heating loads (i.e. solar fraction=70%). The principal reason for the lower-than-expected solar fraction was the SSTES’s high rate of heat loss (twice the expected rate). Its storage efficiency (i.e. heat extraction/heat injection) was only 20%. Analysis of the experimental data shows one side of the SSTES loses heat faster than the other sides. It is hypothesized that the SSTES’s insulation has become partially degraded; the numerical model was modified to reflect this. The final model has been validated through comparison to the experimental data using several key metrics that are presented and analyzed in this work.

ABSTRACTEnergy conservation in buildings has become a crucial approach to alleviating the energy crisis and reducing carbon emissions. Thermal insulation coatings are one of the effective methods for energy conservation in buildings. In this study, hollow polystyrene microspheres (HPMs) with varying particle sizes and enhanced thermal insulation performance were synthesized via seeded emulsion polymerization combined with alkali swelling. By adjusting the initiator content, core particle sizes were controlled between 142 and 354 nm, yielding HPMs with particle sizes ranging from 364 to 550 nm and cavity diameters from 127 to 370 nm. At a 40 wt% HPMs‐0.775 loading, the composite coating exhibited enhanced solar reflectance (98.1% ± 0.7%) due to the synergistic effects of light reflection and thermal insulation from the hollow interiors. The coating's average transmittance was 6.5% ± 1.3%, and its average reflectance reached 43.1% ± 1.4%. The thermal conductivity of the coating (0.1098 ± 0.0056 W/m K) was found to be significantly lower than that of all other tested compositions.

System Approach for Building Energy Conservation

Energy harvesting, reuse and upgrade to reduce primary energy usage in the USA

Domestic hot water (DHW) and space heating (SH) are occupying more than 65% of carbon dioxide emissions in the residential sector.As global warming is critical issue, reducing carbon dioxide emissions is essential by decreasing fossil fuel energy use and improving energy efficiency.Air source heat pumps (ASHPs) are promising technologies that can provide DHW and SH with higher energy efficiency with less carbon dioxide emissions than conventional gas boiler systems [1].Recently, heat pumps (HPs) integrated with photovoltaic thermal modules (PVT), referred to as PVT-HP or solar-assisted heat pump (SAHP), have gained attention.PVT system can reduce HP operation time and power consumption, resulting in increased overall efficiency.However, owing to the imbalance between energy demand and the supply of renewable energy in these systems, thermal energy storage (TES) is required.Additionally, TES acts as a buffer tank, contributing to a reduction in the heating capacity required from the HP [2].Various studies have been conducted on SAHP and TES.Bae et al.[3] experimentally investigated the effect of the PVT-ASHP integrated with two water storages for DHW and space heating.The coefficient of performance (COP) of the system improved by approximately 52% compared to the ASHP system.Huan et al. [4] found that the parallel SAHP achieved 34.4% higher COP than the serial SAHP during the annual operation of a hot water supply system at a university in Xi'an, China.For TES, phase change materials (PCMs) have been gaining attention owing to their significant latent heat during phase transition.Cunha et al. [5] denoted that a SAHP with PCM TES system could store more energy within narrower temperature range than water storage, resulting in 56% reduction of annual CO 2 emissions, and energy savings of 76% compared to the conventional gas boiler system.However, research on PVT-ASHP system integrated with PCM TES is limited.In this study, the annual energy performances of DHW systems are analysed using the dynamic simulation program TRNSYS.Parallel solar-assisted air source heat pump (SAASHP) integrated with two different TESs, PCM TES and water storage, are selected as the analysed system.DHW load profile is set according to the 210 L water tank load profile in the European standard EN 16147[6].For the solar source, a PVT module with 1.58 m 2 absorber area is selected.System COP, electrical power, and thermal energy are primarily used as energy performance parameters.As a result, the SAASHP with PCM TES shows 9.2% higher system COP than the SAASHP with water storage through a year.The annual electricity generations of the PVT module for both cases are 931 MJ.The thermal energy generation of the PVT module of the PCM TES case is 8.1% higher than that of the water storage case owing to PCM TES's superior thermal characteristics.PCM TES demonstrates an isothermal characteristic during charging and discharging, which contributes to a lower temperature of the circulating water through the condenser of ASHP and PVT module compared to that of water storage.The lower circulating water temperature results in higher ASHP COP and larger thermal energy generation from PVT, leading to better overall system COP compared to the water storage case.However, the total amount of thermal energy from PVT is only 0.5% of the energy demand for DHW owing to the limited PVT area.Further optimization of the PVT module area can lead to more effective system configuration.