Introducing a Novel Air Handling Unit Based on Focusing on Turbulent Exhaust Air Energy-Exergy Recovery Potential

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Yuanzhou Zheng ◽  
Rasool Kalbasi ◽  
Arash Karimipour ◽  
Peng Liu ◽  
Quang-Vu Bach
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Energy Recovery ◽  
Primary Energy ◽  
Second Law ◽  
The Novel ◽  
Heating Coil ◽  
Recovery Potential ◽  
Air Handling Unit ◽  
Second Law Analysis

Abstract A novel air handling unit (AHU) aimed at reducing energy consumption was introduced in this study. In the proposed novel AHU, the heating coil is completely removed, and therefore, no heating coil energy demand is needed. The novel AHU used primary energy recovery as well as secondary one to utilize the return air energy and exergy. Through the first energy recovery unit, the return air exergy was recovered, while in the secondary heat exchanger, return air energy was recycled. Results showed that using the novel AHU leads to a reduction in energy consumption as well as the exergy losses. Three climate zones of A, B, and C were selected to assess the novel AHU performance. From the first law viewpoint, at zone B, using novel AHU has priority over other zones, while in the second law analysis, utilizing the novel AHU at zones B and C is more beneficial. Based on the first law analysis, owing to using novel AHU, energy consumption reduced up to 55.2% at Penang climate zone. Second law analysis revealed that utilizing the novel AHU decreased the irreversibility up to 51.4% in the Vancouver climate region.

scholarly journals Energy Recovery Potential in Industrial and Municipal Wastewater Networks Using Micro-Hydropower in Spain

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
Aida Mérida García ◽  
Juan Antonio Rodríguez Díaz ◽  
Jorge García Morillo ◽  
Aonghus McNabola
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Recovery ◽  
Energy Production ◽  
Municipal Wastewater ◽  
Distribution Networks ◽  
Total Power ◽  
Energy Potential ◽  
Total Energy Consumption ◽  
Recovery Potential

The use of micro-hydropower (MHP) for energy recovery in water distribution networks is becoming increasingly widespread. The incorporation of this technology, which offers low-cost solutions, allows for the reduction of greenhouse gas emissions linked to energy consumption. In this work, the MHP energy recovery potential in Spain from all available wastewater discharges, both municipal and private industrial, was assessed, based on discharge licenses. From a total of 16,778 licenses, less than 1% of the sites presented an MHP potential higher than 2 kW, with a total power potential between 3.31 and 3.54 MW. This total was distributed between industry, fish farms and municipal wastewater treatment plants following the proportion 51–54%, 14–13% and 35–33%, respectively. The total energy production estimated reached 29 GWh∙year−1, from which 80% corresponded to sites with power potential over 15 kW. Energy-related industries, not included in previous investigations, amounted to 45% of the total energy potential for Spain, a finding which could greatly influence MHP potential estimates across the world. The estimated energy production represented a potential CO2 emission savings of around 11 thousand tonnes, with a corresponding reduction between M€ 2.11 and M€ 4.24 in the total energy consumption in the country.

scholarly journals Energy Embedded in Food Loss Management and in the Production of Uneaten Food: Seeking a Sustainable Pathway

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 767 ◽  
Author(s):  
Daniel Hoehn ◽  
María Margallo ◽  
Jara Laso ◽  
Isabel García-Herrero ◽  
Alba Bala ◽  
...  
Keyword(s):  
Supply Chain ◽  
Energy Loss ◽  
Food Supply ◽  
Energy Demand ◽  
Energy Recovery ◽  
Primary Energy ◽  
Food Supply Chain ◽  
Food Loss ◽  
Food Energy ◽  
Primary Energy Demand

Recently, important efforts have been made to define food loss management strategies. Most strategies have mainly been focused on mass and energy recovery through mixed food loss in centralised recovery models. This work aims to highlight the need to address a decentralised food loss management, in order to manage the different fractions and on each of the different stages of the food supply chain. For this purpose, an energy flow analysis is made, through the calculation of the primary energy demand of four stages and 11 food categories of the Spanish food supply chain in 2015. The energy efficiency assessment is conducted under a resource use perspective, using the energy return on investment (EROI) ratio, and a circular economy perspective, developing an Energy return on investment – Circular economy index (EROIce), based on a food waste-to-energy-to-food approach. Results suggest that the embodied energy loss consist of 17% of the total primary energy demand, and related to the food categories, the vegetarian diet appears to be the most efficient, followed by the pescetarian diet. Comparing food energy loss values with the estimated energy provided for one consumer, it is highlighted the fact that the food energy loss generated by two to three persons amounts to one person's total daily intake. Moreover, cereals is the category responsible for the highest percentage on the total food energy loss (44%); following by meat, fish and seafood and vegetables. When the results of food energy loss and embodied energy loss are related, it is observed that categories such as meat and fish and seafood have a very high primary energy demand to produce less food, besides that the parts of the food supply chain with more energy recovery potential are the beginning and the end. Finally, the EROIce analysis shows that in the categories of meat, fish and seafood and cereals, anaerobic digestion and composting is the best option for energy recovery. From the results, it is discussed the possibility to developed local digesters at the beginning and end of the food supply chain, as well as to developed double digesters installations for hydrogen recovery from cereals loss, and methane recovery from mixed food loss.

scholarly journals From Entropy Generation to Exergy Efficiency at Varying Reference Environment Temperature: Case Study of an Air Handling Unit

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 361 ◽  
Author(s):  
Giedrė Streckienė ◽  
Vytautas Martinaitis ◽  
Juozas Bielskus
Keyword(s):  
Heat Pump ◽  
Entropy Generation ◽  
Energy Demand ◽  
Dynamic Modelling ◽  
Second Law Of Thermodynamics ◽  
Exergy Efficiency ◽  
Second Law ◽  
Air Handling Unit ◽  
Individual Character ◽  
Environment Temperature

The continuous energy transformation processes in heating, ventilation, and air conditioning systems of buildings are responsible for 36% of global final energy consumption. Tighter thermal insulation requirements for buildings have significantly reduced heat transfer losses. Unfortunately, this has little effect on energy demand for ventilation. On the basis of the First and the Second Law of Thermodynamics, the concepts of entropy and exergy are applied to the analysis of ventilation air handling unit (AHU) with a heat pump, in this paper. This study aims to develop a consistent approach for this purpose, taking into account the variations of reference temperature and temperatures of working fluids. An analytical investigation on entropy generation and exergy analysis are used, when exergy is determined by calculating coenthalpies and evaluating exergy flows and their directions. The results show that each component of the AHU has its individual character of generated entropy, destroyed exergy, and exergy efficiency variation. However, the evaporator of the heat pump and fans have unabated quantities of exergy destruction. The exergy efficiency of AHU decreases from 45–55% to 12–15% when outdoor air temperature is within the range of −30 to +10 °C, respectively. This helps to determine the conditions and components of improving the exergy efficiency of the AHU at variable real-world local climate conditions. The presented methodological approach could be used in the dynamic modelling software and contribute to a wider application of the Second Law of Thermodynamics in practice.

scholarly journals Energy Conservation and Efficiency by Energy Efficient Motor in India

2019 ◽  
Vol 9 (1) ◽  
pp. 3917-3926
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Greenhouse Gas ◽  
Energy Efficient ◽  
Energy Demand ◽  
Industrial Sector ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Ghg Emission ◽  
The Government

Electricity demand in India is increasing at a rapid pace because of growth in Economy, urbanization, infrastructure development and the living standard of people. According to the United Nation’s world population prospects (2017), India’s population is 1.34 billion which will go grow further and surpass China by 2025[1]. According to the IMF, the Indian economy is expected to grow by 7.5% in FY19-20 and 7.7% in FY20-21[2]. Increased population and growth in GDP are associated with increased energy demand. India’s primary energy consumption was 754 Mtoe in 2017 and expected to reach 1928 Mtoe in 2040[3]. Major energy demand is from the Industrial sector which was 51% of total primary energy consumption in 2017 and expected to reach 990 Mtoe, by 2040 [3]. Rising energy demand and dependence on coal-based energy generation capacity, leading to the emission of Green House Gases (GHG). Most of India’s Greenhouse gas emissions are from energy sector having 68.7% contribution in overall greenhouse gas emission. Agriculture, Industrial process land-use change and forestry (LUCF), and waste, contributed 6.0%, 3.8% and 1.9% respectively in overall GHG emission in 2014. [4]. Reducing the GHG emission in India is a major challenge in front of the Government as the Government has to maintain sustainable growth with the contribution in mitigating the effect of climate change. Govt. has pledged to Paris Agreement for the reduction in emission intensity of GDP by 33-35% by 2030 below 2005 level [5]. In the reduction of GHG emission, energy efficiency's contribution is estimated at approx. 51% [6]. The industrial sector can contribute most in reducing GHG emission and contributes to nationally determined contribution. Industry consumes 40%-45% of total energy consumption and motor-driven system consumes 70% [7] of total Industrial energy. Most of the energy in Industries are consumed to run the motor for various purposes and consumes a major chunk of energy which can be reduced to a significant level by replacing the standard motor with energy efficient motor. 90% of the motor in Indian industries are IE1 or below IE1 standard [8] and required replacement. By installing the energy efficient motor, the industry can save huge energy, cost and reduce CO2 emission. Observing the opportunity for energy saving by energy efficient motor, this paper aims to analyze how energy efficient motor is capable of reducing energy consumption, and how it can contribute to energy conservation. Methodology adopted in this paper is secondary research, that answers to questions like; why Industry need energy efficient motor, how energy efficient motor can save energy and increases efficiency, cost-benefit analysis of installing energy efficient motor, barriers to the installation of energy efficient motor and solution to those barriers in migration from the standard motor to energy efficient motor in India.

scholarly journals The influence of crop dryer operation parameters on the efficiency of energy recovery from extract air

2019 ◽  
Vol 116 ◽  
pp. 00064
Author(s):  
Edward Przydróżny ◽  
Aleksandra Przydróżna ◽  
Sylwia Szczęśniak ◽  
Juliusz Walaszczyk
Keyword(s):  
Air Temperature ◽  
Thermal Energy ◽  
Energy Demand ◽  
Energy Recovery ◽  
Primary Energy ◽  
Specific Humidity ◽  
Primary Energy Demand ◽  
Air Temperatures ◽  
Flow Surface ◽  
Recovery System

Crop drying, especially maize drying, occurs at low external air temperatures, which are lower than the extract air temperature. Therefore, using heat exchangers, to recover thermal energy from the extract air to preheat the cold and dry external air, results in a significant reduction in the primary energy demand for crop drying. The measurements of air parameters in the crop dryer, with a drying capacity of 19 Mg/h of maize, confirm the assumptions undertaken for the production of the heat recovery system. We apply the cross-counter-flow surface heat exchanger system to provide a significant improvement in the efficiency of crop drying. We perform the analysis of the thermal energy recovery system operation. Our results indicate the influence of the drying air set-point and the crop specific humidity on the efficiency of energy recovery from the exhaust air. We performed our measurements at different drying air temperature set-points and different crop relative humidity.

Differences Between Second Law Analysis and Pinch Technology

1995 ◽  
Vol 117 (3) ◽  
pp. 186-191 ◽  
Author(s):  
D. A. Sama
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Maximum Energy ◽  
Global Optimum ◽  
Second Law ◽  
Heat Exchanger Network ◽  
Second Law Analysis ◽  
Heat Exchanger Networks ◽  
Pinch Technology ◽  
Correct Design

The use of second law analysis to design a heat exchanger network is compared with the pinch technology approach. Differences between the two methods are identified and discussed in the light of claims made by practitioners of pinch technology. Second law insights are used to easily identify and correct design errors in a heat exchanger network, and to design maximum energy recovery networks. More importantly, it is found that use of the second law provides an understanding of the process which is totally absent in the pinch technology approach. The claims that pinch technology can find global optimum solutions, that only pinch technology can find maximum energy recovery heat exchanger networks, and that pinch technology is a form of second law analysis, are considered, discussed, and shown to be invalid.

scholarly journals Thermodynamical motivation of the Polish energy policy

2011 ◽  
Vol 33 (4) ◽  
pp. 3-21 ◽  
Author(s):  
Andrzej Ziębik
Keyword(s):  
Energy Policy ◽  
High Efficiency ◽  
Second Law Of Thermodynamics ◽  
Primary Energy ◽  
Point Of View ◽  
Second Law ◽  
Special Importance ◽  
Second Law Analysis ◽  
Transmission And Distribution ◽  
Exergy Losses

Abstract Basing on the first and second law of thermodynamics the fundamental trends in the Polish energy policy are analysed, including the aspects of environmental protection. The thermodynamical improvement of real processes (reduction of exergy losses) is the main way leading to an improvement of the effectivity of energy consumption. If the exergy loss is economically not justified, we have to do with an error from the viewpoint of the second law analysis. The paper contains a thermodynamical analysis of the ratio of final and primary energy, as well as the analysis of the thermo-ecological cost and index of sustainable development concerning primary energy. Analyses of thermo-ecological costs concerning electricity and centralized heat production have been also carried out. The effect of increasing the share of high-efficiency cogeneration has been analyzed, too. Attention has been paid to an improved efficiency of the transmission and distribution of electricity, which is of special importance from the viewpoint of the second law analysis. The improvement of the energy effectivity in industry was analyzed on the example of physical recuperation, being of special importance from the point of view of exergy analysis.

scholarly journals Cost-Benefit Analysis of Hybrid Photovoltaic/Thermal Collectors in a Nearly Zero-Energy Building

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1582 ◽  
Author(s):  
Conti ◽  
Schito ◽  
Testi
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electrical Energy ◽  
Energy System ◽  
Primary Energy ◽  
Hot Water ◽  
Solar Thermal ◽  
Primary Energy Consumption ◽  
Solar Thermal Energy ◽  
Zero Energy

This paper analyzes the use of hybrid photovoltaic/thermal (PVT) collectors in nearly zero-energy buildings (NZEBs). We present a design methodology based on the dynamic simulation of the whole energy system, which includes the building energy demand, a reversible heat pump as generator, the thermal storage, the power exchange with the grid, and both thermal and electrical energy production by solar collectors. An exhaustive search of the best equipment sizing and design is performed to minimize both the total costs and the non-renewable primary energy consumption over the system lifetime. The results show that photovoltaic/thermal technology reduces the non-renewable primary energy consumption below the nearly zero-energy threshold value, assumed as 15 kWh/(m2·yr), also reducing the total costs with respect to a non-solar solution (up to 8%). As expected, several possible optimal designs exist, with an opposite trend between energy savings and total costs. In all these optimal configurations, we figure out that photovoltaic/thermal technology favors the production of electrical energy with respect to the thermal one, which mainly occurs during the summer to meet the domestic hot water requirements and lower the temperature of the collectors. Finally, we show that, for a given solar area, photovoltaic/thermal technology leads to a higher reduction of the non-renewable primary energy and to a higher production of solar thermal energy with respect to a traditional separate production employing photovoltaic (PV) modules and solar thermal (ST) collectors.

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