scholarly journals The effect of a density gradient in groundwater on ATES system efficiency and subsurface space use

2018 ◽  
Vol 45 ◽  
pp. 85-103
Author(s):  
Martin Bloemendal ◽  
Theo N. Olsthoorn

Abstract. A heat pump combined with Aquifer Thermal Energy Storage (ATES) has high potential in efficiently and sustainably providing thermal energy for space heating and cooling. This makes the subsurface, including its groundwater, of crucial importance for primary energy savings. ATES systems are often placed in aquifers in which salinity increases with depth. This is the case in coastal areas where also the demand for ATES application is high due to high degrees of urbanization in those areas. The seasonally alternating extraction and re-injection between ATES wells disturbs the preexisting ambient salinity gradient causing horizontal density gradients, which trigger buoyancy flow, which in turn affects the recovery efficiency of the stored thermal energy. This section uses analytical and numerical methods to understand and explain the impact of buoyancy flow on the efficiency of ATES in such situations, and to quantify the magnitude of this impact relative to other thermal energy losses. The results of this research show that losses due to buoyancy flow may become considerable at (a relatively large) ambient density gradients of over 0.5 kg m−3 m−1 in combination with a vertical hydraulic conductivity of more than 5 m day−1. Monowell systems suffer more from buoyancy losses than do doublet systems under similar conditions.

Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 119 ◽  
Author(s):  
Alessia Arteconi ◽  
Luca Del Zotto ◽  
Roberto Tascioni ◽  
Khamid Mahkamov ◽  
Chris Underwood ◽  
...  

In this paper, the smart management of buildings energy use by means of an innovative renewable micro-cogeneration system is investigated. The system consists of a concentrated linear Fresnel reflectors solar field coupled with a phase change material thermal energy storage tank and a 2 kWe/18 kWth organic Rankine cycle (ORC) system. The microsolar ORC was designed to supply both electricity and thermal energy demand to residential dwellings to reduce their primary energy use. In this analysis, the achievable energy and operational cost savings through the proposed plant with respect to traditional technologies (i.e., condensing boilers and electricity grid) were assessed by means of simulations. The influence of the climate and latitude of the installation was taken into account to assess the performance and the potential of such system across Europe and specifically in Spain, Italy, France, Germany, U.K., and Sweden. Results show that the proposed plant can satisfy about 80% of the overall energy demand of a 100 m2 dwelling in southern Europe, while the energy demand coverage drops to 34% in the worst scenario in northern Europe. The corresponding operational cost savings amount to 87% for a dwelling in the south and at 33% for one in the north.


Author(s):  
Jacek Borowski

In this chapter, the impact of climbing plants on facades of buildings and their surroundings is presented. Benefits and risks of plant growth on the walls are discussed with respect to their durability. Economic benefits from the presence of vines are shown including energy savings for home heating and cooling. Additionally, the phytoremediation (cleaning up the environment by plants) properties of vines are describe. It should be stated that climbing plants can contribute to damage only in places where facades are damaged, plaster cracked, or where plants are incorrectly planted.


2020 ◽  
Vol 12 (16) ◽  
pp. 6563
Author(s):  
Roque G Stagnitta ◽  
Matteo V Rocco ◽  
Emanuela Colombo

Energy balances have been historically conceived based on a supply-side perspective, providing neither detailed information about energy conversion into useful services nor the effects that may be induced by the application of policies in other sectors to energy consumption. This article proposes an approach to a thorough assessment of the impact of efficiency policies on final energy uses, focusing on residential space heating and cooling, and capable of: (1) quantifying final useful services provided and (2) accounting for the global impact of efficiency policies on final energy use, taking advantage of Input–Output analysis. This approach is applied in five cities of Argentina. Firstly, the quantity of energy service provided (i.e., level of thermal comfort) for each city is evaluated and compared with the defined target. It is found out that heating comfort is guaranteed approximately as established, whereas in the cooling case the provision is twice the established level. Secondly, primary energy consumption of heating and cooling services is evaluated before and after different efficiency improvement policies. The results show that the major primary energy saving (52%) is obtained from the upgrading appliances scenario and reflect the importance of accounting for embodied energy in goods and services involved in interventions.


2018 ◽  
Vol 10 (12) ◽  
pp. 4856 ◽  
Author(s):  
Hyung An ◽  
Jong Yoon ◽  
Young An ◽  
Eunnyeong Heo

This study analyzed the heating and cooling performance of an office building in Daegu, Korea, equipped with amorphous-Si (a-Si) building-integrated photovoltaic (BIPV) windows. EnergyPlus was used to simulate and compare the heating and cooling loads of models for clear glass double-layer, heat-absorbing glass double-layer, and low-emissivity (low-e) glass double-layer windows. In addition, the impact of changes in building operation time, temperature settings, air infiltration from the entrances, and internal load were also analyzed as these all have a large impact on heating and cooling loads. Finally, three types of heating and cooling equipment were tested, and their power and primary energy consumption analyzed, to determine the actual energy used. Under baseline conditions, there was an 18.2% reduction in heating and cooling loads when the BIPV model was used compared to when the clear glass double-layer window was used. In addition, increases in temperature settings and air infiltration from the entrances had a negative effect on the reduction of the heating and cooling loads demonstrating a need for intensive management of these features if a-Si BIPV windows are installed in a building.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Baurzhan Jangeldinov ◽  
Shazim Ali Memon ◽  
Jong Kim ◽  
Marzhan Kabdrakhmanova

Phase change materials have been applied to a building framework to decrease energy and fossil fuel consumption as well as make the building sector more sustainable. Lightweight structures are attractive and increasingly being used in residential buildings. Hence, in this research, the energy efficiency and thermal performance of buildings located in eight various cities (Helsinki, Kiev, Saint Petersburg, Moscow, Stockholm, Toronto, Montreal, and Kiev) of warm summer humid continental climate (Dfb) were evaluated. The impact of heating and cooling energy savings pattern on the selection of optimum phase change material for each city has been demonstrated. In addition, the impact of volume of PCM, precisely the effect of varying and constant volume, on energy savings was assessed for the lightweight steel-framed building. Simulations were performed in EnergyPlus by applying eleven melting temperature ranges of PCM. Test results demonstrated that energy savings were higher in the swing season and the maximum temperature reduced during these months was 3.3°C. Heating and cooling energy savings were found to strongly influence the selection of optimum PCM. In cities where cooling energy savings were the highest, the optimum PCMs were PCMs 24-26 while in cities where heating energy savings were the highest, the optimum PCM was found to be PCM 21. For constant volume, the performance of optimum PCM raised when the surface area was enlarged, while the thickness of PCM was reduced. Overall, the application of PCM into lightweight steel-framed residential structure located in warm summer humid continental climate region is a feasible option.


Author(s):  
V. N. Bartari ◽  
S. P. S. Rajput

In HVAC applications, huge amount of energy is utilized in fans and blowers to maintain the flow. In this paper energy savings associated with air distribution is discussed. In a most commonly used air distribution system, uniform thermal environment in the occupied space is established. An alternative to this method is the under floor air distribution system (UFAD) which is in its fantasy state. Thermal stratification can be established in this method due to the buoyancy flow of the air. In this paper assessment of the impact of temperature sensors in energy savings is done in UFAD system. It is observed that by the placement of temperature sensors in the occupied space, supply air temperature can be controlled while maintaining the comfort conditions. By optimal conditions of the temperature and volume flow, energy savings can be achieved due to reduction in energy requirements in refrigeration and ventilation. The comfort criteria of ASHRAE standard 55-92 is taken.


Author(s):  
Fahad Almehmadi ◽  
Kevin Hallinan

Abstract Appropriate greenhouse microclimate control is essential for optimizing plant growth and food production. But, maintenance of a greenhouse microclimate generally requires an excessive amount of energy. According to a report published by Scott Sanford [1], the energy cost for greenhouses is considered the third highest annual cost, behind labor and plant materials. At northern latitudes, heating is the primary energy requirement needed in an agriculture greenhouse, comprising 70 to 80% of a typical greenhouse energy consumption [1]. A reduction of heating energy is necessary to ensure the economic viability of a greenhouse. This research investigates the potential energy savings associated with integrating a solar air heater assisted with a desiccant wheel in an agriculture greenhouse. This study has two main thrusts. The first is to demonstrate the energy effectiveness a solar air heater with a dehumidification system to maintain the internal climate. The second thrust is to develop a multi-linear regression model that can be used to predict the hourly heating requirement. Thereafter, the developed regression model can be used to conduct a parametric analysis to investigate the impact of changing greenhouse parameters on the total heating requirements. A case study has been considered for a greenhouse that is 30 m long and 24 m wide. The climate condition of the city of Dayton, OH was selected for this case. The predicted performance of the integrated system is compared with two other heating systems: electric and gas furnaces. The study reveals that heating energy savings in the proposed system is 51% and 30% when compared with the electric and gas furnaces, respectively. Aside from heating energy savings, the proposed system can be efficiently used to control indoor humidity in a way that ensures better crop yield.


2020 ◽  
Vol 12 (23) ◽  
pp. 9893
Author(s):  
Tudor Cioara ◽  
Marcel Antal ◽  
Claudia Daniela Antal (Pop) ◽  
Ionut Anghel ◽  
Massimo Bertoncini ◽  
...  

In this paper, we address the management of Data Centers (DCs) by considering their optimal integration with the electrical, thermal, and IT (Information Technology) networks helping them to meet sustainability objectives and gain primary energy savings. Innovative scenarios are defined for exploiting the DCs electrical, thermal, and workload flexibility as a commodity and Information and Communication Technologies (ICT) are proposed and used as enablers for the scenarios’ implementation. The technology and scenarios were evaluated in the context of two operational DCs: a micro DC in Poznan which has on-site renewable sources and a DC in Point Saint Martin. The test cases’ results validate the possibility of using renewable energy sources (RES) for exploiting DCs’ energy flexibility and the potential of combining IT load migration with the availability of RES to increase the amount of energy flexibility by finding a trade-off between the flexibility level, IT load Quality of Service (QoS), and the RES production level. Moreover, the experiments conducted show that the DCs can successfully adapt their thermal energy profile for heat re-use as well as the combined electrical and thermal energy profiles to match specific flexibility requests.


2019 ◽  
Vol 116 ◽  
pp. 00096
Author(s):  
Małgorzata Wesołowska ◽  
Marta Laska

People living in urban areas are exposed to a number of threats related with dense urban tissue and high number of vehicles. These include air pollutions, traffic noise and high temperatures. In addition, large cities are struggling with high energy consumption for heating and cooling purposes. One of the possibilities to reduce the mentioned undesirable effects is the use of vegetation on the walls. Plants absorbs the pollutants of air, produced the oxygen, mounted on external walls create thermal insulation and positively affect the psychological aspect. Green walls can be used both indoors and outdoors. The article presents literature review on green walls, describes their benefits and presents the calculations SPBT and possible energy savings taking into account the transmission losses for small residential building.


Lubricants ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 117
Author(s):  
Raj Shah ◽  
Rui Chen ◽  
Mathias Woydt

Primary energy has become a vital part of society—from mobility, heating, and cooling to refrigeration to preserve food as well as for simple communication methods, such as texting. As such, pollution and environmental concerns regarding the impact of human activities have become mainstream and efforts have been made to reduce solid wastes as well as CO2 and greenhouse gas emissions. Renewable energy is almost synonymous with environmentally friendly. While energy conversion from fossil fuels and natural gases is responsible for most of the pollution (CO2, NOx, SO2, particulate matter (PM), etc.) in modern society, these processes also generated 86% of global primary energy in 2019. Furthermore, as humans become more dependent on energy, power demands will only increase with time. Material hunger represents another little perceived dependency of human prosperity. The longevity of products and goods is crucial to limit CO2eq emissions associated with material streams. This paper will focus on two relationships: that of CO2 and friction, and that of sustainability and wear protection.


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