•Cascade PCM as potential low cost and high energy TES systems.•Daily, monthly, and annual transient model of the plant performance with cascade PCM.•Similarity of PCM and double tank storage system ...in CSP.
Concentrated solar power (CSP) is today recognized as a unique renewable energy for electricity generation due to its capability to provide dispatchable electricity incorporating thermal energy storage (TES). Molten salts TES is the most widespread technology in commercial CSP but the industry is looking for cheaper and more efficient TES systems and phase change materials (PCM) have been highlighted as potential low cost and high energy TES systems. This paper presents a completely new concept of PCM energy storage systems to be used in solar thermal electricity plants with its technical assessment. A cascade type PCM storage system is evaluated, using four buckets with the PCM organized based on melting temperature and the latent energy of the materials. Daily, monthly, and annual transient simulations of the plant performance are carried out. The main conclusion is the similarity between this new concept and the commercial two-tank indirect molten salt system. The cumulative power production over the year is similar and the net production of both systems is well matched.
•Systematic review of the technological options to achieve zero energy buildings.•Relevant literature published was critically assessed.•With appropriate design, buildings can contribute to climate ...change mitigation.•Decreasing the embodied energy in the materials used in their construction.•Decreasing the energy demand and use during their operation phase.
A systematic review of the technological options and strategies to achieve zero energy buildings was carried out to establish today state-of-the-art knowledge base and to present key design and performance factors that define those technologies with the final aim of contributing to climate change mitigation options of buildings. All relevant literature published from January 2013 to August 2019 was critically assessed. A total of 14,895 papers were identified and 220 reviews were evaluated as first literature source; this literature showed that the published information is diverse and not organized, therefore climates and building typologies is not possible solely through published information. Collected evidence shows that with appropriate design, buildings can contribute to climate change mitigation decreasing the embodied energy in the materials used in their construction and decreasing the energy demand and use during their operation phase.
Sorption is used for absorption/adsorption heat pumps (sorption refrigeration) and sorption for thermal energy storage (TES). This paper is the first review where the research on both applications is ...shown together. Sorption has advanced very much due to the immense amount of research carried out around heat pumping and solar refrigeration. Moreover, sorption and thermochemical heat storage attracted considerable attention recently since this technology offers various opportunities in the design of renewable and sustainable energy systems. The paper presents the operation principle of the technology and the materials used or in research are listed and compared. Absorption heat pumping and refrigeration research is today more focussed in the decrease of unit costs and increase of energy efficiency, adsorption is focussed in finding more efficient working pairs, and storage is testing the first prototypes and designing new ones with different or enhanced storage materials and new reactor concepts to optimize energy output.
•Sorption is used for absorption/adsorption heat pumps and for thermal energy storage.•First review where the research on the above applications is shown together.•Ab/adsorption research has focused on materials and system improvement.•Storage research is developing prototypes to demonstrate the technology.
•Industrial activities have a huge potential for waste heat recovery.•TES systems overcome the intermittence and distance of the IWH source.•More than 35 IWH case studies of on-site and off-site TES ...systems are reviewed.•On-site TES systems in the basic metals manufacturing are the most recurrent option.•Water, erythritol and zeolite are the TES materials more used in IWH recovery.
Industrial activities have a huge potential for waste heat recovery. In spite of its high potential, industrial waste heat (IWH) is currently underutilized. This may be due, on one hand, to the technical and economic difficulties in applying conventional heat recovery methods and, on the other, the temporary or geographical mismatch between the energy released and its heat demand. Thermal energy storage (TES) is a technology which can solve the existing mismatch by recovering the IWH and storing it for a later use. Moreover, the use of recovered IWH leads to a decrease of CO2 emissions and to economic and energy savings. Depending on the distance between the IWH source and the heat demand, TES systems can be placed on-site or the IWH can be transported by means of mobile TES systems, to an off-site heat demand. Around 50 industry case studies, in which both on-site and off-site recovery systems are considered are here reviewed and discussed taking into account the characteristics of the heat source, the heat, the TES system, and the economic, environmental and energy savings. Besides, the trends and the maturity of the cases reviewed have been considered. On-site TES systems in the basic metals manufacturing are the technology and industrial sector which has focused the most attention among the researchers, respectively. Moreover, water (or steam), erythritol and zeolite are the TES materials used in most industries and space comfort and electricity generation are the most recurrent applications.
•Detailed bibliometric analysis about TES applied to the built environment.•Three different queries to include buildings, districts, roads, and bridges.•Scientific publications were obtained from ...Scopus database on September 2020.•The co-occurrence of the keywords was analysed through the software VOSviewer.•Hotspots and Research gaps for the built environment were identified.
The energy consumption in the built environment represents one of the major contributors of carbon emissions to the atmosphere. This leads to the need for a transition in the building sector and the introduction of policies that pursue high efficiency in residential and non-residential buildings with an increasing share of renewables. The benefit of the use of thermal energy storage is widely recognized to increase the efficiency of energy systems in different building typologies, to help in the introduction of renewable energies in buildings and to reduce the energy demand needed for heating and cooling. Nowadays, different thermal energy storage technologies are available, including sensible, latent, and sorption and chemical reactions (also called thermochemical) energy storage. Although in the past twenty years, the scientific literature showed an increasing trend in the research of thermal energy storage integrated to the building sector, it was only in recent years that this concept was extended to the built environment, which includes residential and non-residential buildings, districts, and urban networks. This paper provides a comprehensive review and classification of thermal energy storage technologies applied in the built environment considering the trends and the future perspective of the past and current research.
High temperature thermal energy storage offers a huge energy saving potential in industrial applications such as solar energy, automotive, heating and cooling, and industrial waste heat recovery. ...However, certain requirements need to be faced in order to ensure an optimal performance, and to further achieve widespread deployment. In the present review, these requirements are identified for high temperature (>150°C) thermal energy storage systems and materials (both sensible and latent), and the scientific studies carried out meeting them are reviewed. Currently, there is a lack of data in the literature analysing thermal energy storage from both the systems and materials point of view. In the part 1 of this review more than 25 requirements have been found and classified into chemical, kinetic, physical and thermal (from the material point of view), and environmental, economic and technologic (form both the material and system point of view). The enhancements focused on the thermal conductivity are addressed in the Part 2 of this review due to their research significance and extension.
Thermal energy storage and conversion aims to improve the high inefficiency of the industrial processes and renewable energy systems (supply versus demand). Chemical sorption processes and chemical ...reactions based on solid–gas systems are a promising way to store and convert thermal energy for heating or cooling applications and, thereby to increase the efficiency of the processes and to reduce the greenhouse effect. Although more efforts are required to bring this technology to the market, some important breakthrough have been made regarding to system efficiency. Over the last two decades, the experimental research in this field has increased largely to validate these advances under practical conditions. Therefore, this paper gives a state-of-art review of performances obtained under practical conditions by the different prototypes built over the last two decades. In addition, the main advantages and disadvantages of solid–gas chemical sorption processes and chemical reactions are summarized.
In accordance to the current worldwide trend of reducing CO2 emissions and to make the industry more competitive incrementing its efficiency, some countries are starting to quantify their quantity of ...Industrial Waste Heat. In fact, to be able to recover and reuse this waste heat from industrial processes as a source for other processes or activities, the availability of reliable data of the Industrial Waste Heat potential found in a region is a key point. For that, after an exhaustive literature research, this article shows Industrial Waste Heat data from 33 countries and 6 subregions of different countries. Their feasibility is assessed in the discussion part as it is expected and shown in most of the cases that the amount of Industrial Waste Heat is proportional to some parameters regarding the country and its industry like: the Energy Consumed by the Country, the Energy Consumed by the Industry and the amount of Industrial Waste Heat Intensive Industry in the country. Country scale has been chosen and it is shown that at other scales these parameters are not always available. Nevertheless, some of the studied cases found show data not fitting into this pattern (approximately 1/6 of the data found). That can be explained taking into account that in most of the studies the methodology to account the quantity of Industrial Waste Heat is not explained. Factors like the reference year of the data, the boundaries of the analysis, the type of waste heat considered, etc. affect to the report of quantity of Industrial Waste Heat. Therefore, the authors provide a set of parameters and recommend checking these in order to confirm the reliability of data referring to Industrial Waste Heat quantities.
It is well known that there is a need to develop technologies to achieve thermal comfort in buildings lowering the cooling and heating demand. Research has shown that thermal energy storage (TES) is ...a way to do so, but also other purposes can be pursued when using TES in buildings, such as peak shaving or increase of energy efficiency in HVAC systems. This paper reviews TES in buildings using sensible, latent heat and thermochemical energy storage. Sustainable heating and cooling with TES in buildings can be achieved through passive systems in building envelopes, Phase Change Materials (PCM) in active systems, sorption systems, and seasonal storage.
The purpose of this paper is to provide a source of information on thermal energy use in buildings, its drivers, and their past, present and future trends on a global and regional basis. Energy use ...in buildings forms a large part of global and regional energy demand. The importance of heating and cooling in total building energy use is very diverse with this share varying between 18% and 73%. Biomass is still far the dominant fuel when a global picture is considered; the role of electricity is substantially growing, and the direct use of coal is disappearing from this sector, largely replaced by electricity and natural gas in the most developed regions. This paper identifies the different drivers of heating and cooling energy demand, and decomposes this energy demand into key drivers based on a Kaya identity approach: number of households, persons per household, floor space per capita and specific energy consumption for residential heating and cooling; and GDP, floor space per GDP, and specific energy consumption for commercial buildings. This paper also reviews the trends in the development of these drivers for the present, future – and for which data were available, for the past – in 11 world regions as well as globally. Results show that in a business-as-usual scenario, total residential heating and cooling energy use is expected to more or less stagnate, or slightly decrease, in the developed parts of the world. In contrast, commercial heating and cooling energy use will grow in each world region. Finally, the results show that per capita total final residential building energy use has been stagnating in the vast majority of world regions for the past three decades, despite the very significant increases in energy service levels in each of these regions.
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