ABSTRACT
Community greenhouses are important for the production of local food and reduction of food supply insecurities within cities. As we've seen with Covid-19, pandemics highlight the criticality of local food access to underprivileged urban districts. Since almost 60 % of the energy used in greenhouses is spent in heating and cooling, ground heat exchangers (GHEs) can play a significant role in supplying temperature regulation, but geothermal heat pump systems tend to be expensive for community organizations. An efficient way to reduce GHEs installation costs is to dig trenches to install the system horizontally and cover a part of heating and cooling loads only. In order to ensure cost effectiveness and optimize operations, this type of system was studied for urban greenhouses where ground space can be limited. Sizing calculations were performed for GHEs of a 7.62 m x 15.24 m greenhouse located on the Island of Montreal where the annual, monthly, and hourly energy consumption were estimated from previous building simulations. Three scenarios were used to specify sizing of the system in terms of excavation dimensions and percentage of the greenhouse peak loads covered;(1) number and length of trenches required for a horizontal GHE (HGHE) covering 100% of cooling and heating loads;(2) number and length of trenches required for an HGHE to cover 100% of peak heating loads and 60% of peak cooling loads and;(3) the percentage of heating and cooling peak loads that can be covered by an HGHE located under the greenhouse with similar dimensions (around 116 m2). Estimated excavation dimensions for cases 1 and 2 are 51.8 m x 8 m (414.4 m2) and 40.8 m x 8 m (326.4 m2). Estimated percentage of peak loads covered for case 3 is 40% of heating peak loads and 30% of cooling peak loads. © 2022 Geothermal Resources Council. All rights reserved.
ABSTRACT
This paper explores ways to save energy in households with energy prosumers who generate energy using photovoltaic panels and heat pumps. On the basis of a literature analysis, we formulated a research gap in the case of the energy behaviors of prosumers. This research is important due to the growing demand for energy and the transitions of countries toward renewable energy sources. The role of prosumers in the economy is growing as they ensure energy independence and cost savings. The main purpose of this research is to understand the energy behaviors of prosumers and to examine the differences in energy behaviors between users of photovoltaic systems and heat pumps. A sample of 326 Polish prosumer households was selected using the CAWI method in order to obtain empirical data. The results suggest that prosumers show advanced ecological behaviors, and more than half of the respondents implement pro-ecological behaviors in their homes. Being a prosumer is associated with energy independence, which leads to economic stability and less dependence on traditional energy sources. The results indicate that prosumers show a general inclination toward pro-ecological behavior. Thus, this study recommends promoting prosumers and encouraging the use of pro-ecological energy as a priority for the economy. This initiative will contribute to a reduction in energy consumption in various areas, thus raising ecological awareness and a sense of responsibility for the environment.
ABSTRACT
The COVID-19 pandemic created significant challenges in operating the lab component of undergraduate courses and promoting active learning, with only a short time available to implement alternative teaching methods. In this work a low-cost platform for distance operation and assessment of replaceable bench-scale heat exchangers was developed to provide students an opportunity to observe the transient and steady-state behavior of heat exchangers while unable to access lab facilities. Each workbench had a new material cost of approximately C$5 000. Operation of physical equipment provided students the opportunity to observe non-ideal behavior and compare various heat transfer correlations which may not be seen in process simulators. The developed platform implemented an Arduino microcontroller for low-cost process control. Equipment was seamlessly slotted in to the existing course upon the return to on-campus learning and provided a more stable system when compared to previously existing lab experiments. Most learning outcomes were observed in remote and in-lab experiments and challenges faced in remote operation are highlighted. No statistically significant difference was observed in student performance between students completing lab experiments remotely and students completing experiments in-lab. © 2023 Institution of Chemical Engineers
ABSTRACT
Most educators look for experiential learning elements to engage students through interactive concept practice, thus leading their students to reach improved levels of comprehension. The COVID-19 pandemic created a unique challenge for instructors forcing them to adjust their laboratory-based courses and to adapt to a new remote educational medium involving experiential learning. Many innovative ways came to light and were implemented by educators to overcome this challenge. This includes simulations, recorded experiments, and live experiments run by the instructor and watched by students remotely, to name a few. Along the same line of efforts to alleviate challenges to experiential learning imposed by the COVID-19 pandemic, a remotely accessible experimental system was developed, tested, and employed to provide students an interactive and live hands-on learning experience. A heat exchanger system was built and tested with active involvement from students. The system was tested for remote access through an interactive computer interface to run an experiment and obtain measurements of various in-process parameters of the heat exchanger using a data acquisition system. After completion of the testing phase, the system was integrated over two academic terms in a thermal fluid laboratory course. Indirect and direct assessment of students' comprehension and engagement as they used the remote laboratory activity was carried out to evaluate the experiential learning experience for the students. The student feedback regarding remotely operating the heat exchanger system was mostly positive and the direct assessment data shows that the learning experience for students was not impeded during the pandemic due to the utilization of the new device. The system will continue to be implemented face-to-face with option of remote access available in future course offerings. Such a remote laboratory experience has shown great potential to complement and even enhance experiential learning experience of students in a laboratory course. Future plans include building and integrating more similar experimental devices and setups to enhance our preparedness for the unknown. © American Society for Engineering Education, 2022.
ABSTRACT
In recent years, one of the key postulates in the European Union’s policy has become the development of renewable energy sources. In order to achieve the desired synergy effect, the idea of combining two selected sources of energy appeared. This article presents a technical and economic analysis of a hybrid connection of a ground source heat pump with a photovoltaic installation. Taking into account the heat demand of the building, a ground heat pump with a catalog nominal heating power of 25 kW was selected. This article presents the problem of the economic profitability of using a hybrid combination of a heat pump and photovoltaic panels in domestic hot water and central heating systems. The justification for the use of such heat sources in these installations is due to global trends and the gradual departure from conventional energy sources such as oil or gas boilers. This paper presents the economic and ecological results of using the pump heat connected together with photovoltaic panels. In the economic analysis, with the assumed installation costs related to the use of the considered heat pump and PV, two parameters commonly used in the investment analysis (static and dynamic) were used, namely, the simple payback period and the net present value of the investment. For the adopted assumptions, the usable area of the facility and the number of years of use were indicated, at which the investment in question is competitive with other alternative investment interest methods and will start to bring tangible benefits. The performed analysis also has measurable environmental benefits in the form of a reduction in carbon dioxide emissions at the level of 2893 kg/year into the atmosphere. The presented solution will help future investors understand the investment profitability mechanism for their households.
ABSTRACT
A membrane-based enthalpy exchanger is a device used for heat and humidity recovery in ventilated buildings. The energy-saving potential of such a device is dependent on the parameters responsible for heat and moisture recovery. The trend is toward composite membranes, which are custom produced, and their parameters can be adjusted for a given application;therefore, the diffusion and sorption characteristics of such membranes are unknown. In order to obtain the values of the water vapor diffusivity of three investigated handmade membranes, a serial resistance model using a Field and Laboratory Emission Cell (FLEC) is proposed. Experiments were conducted to identify the resistance in each step of the moisture transfer process to extract the moisture diffusivity in the membranes. The calculated moisture diffusivities in the membranes were 8.99 × 10−12 (m2/s) for the membranes from cellulose acetate, 1.9 × 10−10 (m2/s) for the microporous PE/PUR membranes, and 1.53 × 10−11 (m2/s) for the PET/PUR microfibrous membranes. The obtained membrane diffusivities were then used in the proposed effectiveness-NTU-based model of an exchanger with a cross-flow arrangement to predict performance under various operating conditions. The results show that the highest latent effectiveness was found for the exchanger core made from the PE/PUR membrane and the lowest was for the one with the PE/PUR membrane core.
ABSTRACT
This paper demonstrates the need and potential for using waste heat recovery (WHR) systems from infrared gas radiant heaters, which are typical heat sources in large halls, due to the increasing energy-saving requirements for buildings in the EU and the powerful and wide-spread development of the e-commerce market. The types of gas radiant heaters are discussed and the classification of WHR systems from these devices is performed. The article also presents for the first time our innovative solution, not yet available on the market, for the recovery of heat from the exhaust gases of ceramic infrared heaters. The energy analysis for an industrial hall shows that this solution allows for environmental benefits at different levels, depending on the gas infrared heater efficiency, by reducing the amount of fuel and emissions for domestic hot water (DHW) preparation (36.8%, 15.4% and 5.4%, respectively, in the case of low-, standard- and high-efficiency infrared heaters). These reductions, considering both DHW preparation and hall heating, are 16.1%, 7.6% and 3.0%, respectively. The key conclusion is that the innovative solution can spectacularly improve the environmental effect and achieve the highest level of fuel savings in existing buildings that are heated with radiant heaters with the lowest radiant efficiency.
ABSTRACT
Shallow Geothermal Energy (SGE) extracted by Ground Source Heat Pump (GSHP) is a proven clean and profitable technology. Although it is available almost everywhere, its market enjoys different maturity levels along with the other EU Members and even those within the same country. In the Murcia region, in Southern Spain, the presence of GSHP is almost nonexistent. Germany, in contrast, has an extensive tradition of exploiting its SGE resources and is an example of a mature GSHP market. In this work, the technical and non-technical barriers were assessed in both countries to identify the site-specific parameters preventing a better deployment of SGE in Southern Spain. In addition, a SWOT analysis was conducted to highlight the parameters positively and negatively influencing the geothermal resource extraction. Results showed that both study cases showed similar and good technical conditions, such as sufficient resource 80 W/m approx. or a similar impact on the environment mainly due to the use of electricity consumed. However, the regulation and legal framework greatly varied from one area to another. In conclusion, the main factors causing a poor deployment are the lack of specific regulation or regional administration support.
ABSTRACT
Residential biomass combustion has been pointed out as one of the largest sources of atmospheric pollutants. Rising awareness of the environmental effects of residential biomass combustion emissions boosted the development of different emission reduction devices that are currently available on the market for small-scale appliances. However, detailed studies on the efficiency of these devices in different combustion systems available in Southern European countries are lacking. In this study, two pollution control devices (catalytic converter and electrostatic precipitator) were tested in two different combustion systems (batch mode operated woodstove and automatically fed pellet stove) in order to assess the emission reduction potential of the devices. Pine firewood was used to fuel the woodstove. One commercial brand of pellets and an agricultural fuel (olive pit) were taken for the experiments in the pellet stove. While the efficiency of the electrostatic precipitator in reducing PM10 was only recorded for woodstove emissions (29%), the effect of the catalyst in decreasing gaseous emissions was only visible when applied to the pellet stove flue gas. For wood pellet combustion, reductions of CO and TOC emissions were in the range of 60–62% and 74–77%, respectively. For olive pit combustion, a lower decrease of 59–60% and 64% in CO and TOC emissions, respectively, was recorded.
ABSTRACT
As a requirement for sustainable development, air-cycle refrigeration has received wide attention as a candidate for environmentally friendly air conditioning technology. In this study, the thermodynamic performance of air refrigeration cycles is investigated in compartment air conditioning. The effects of compressor efficiency, expander efficiency, ambient humidity, all-fresh-air supply and ambient pressure on the cycle performance are presented. The effects of compressor arrangement in the high-pressure cycle and the low-pressure cycle are compared. An open-loop high-pressure cycle has a larger COP than that of an open-loop low-pressure cycle but requires larger heat exchange. The performance of air refrigeration cycles with full fresh air is studied, and the influence of fresh air is discussed. Schemes for condensed water recirculation with wet compression are proposed, which can improve the COPs of open-loop low-pressure cycles by 44.7%, 48.8% and 48.4%. In the air conditioning of plateau trains, open-loop high-pressure cycles have slightly lower COPs, but they can supply air with elevated pressure and oxygen concentration.
ABSTRACT
In this study, geothermal-based three different systems are examined comparatively and a decision-making method is used to find the best option to use in refugee settlements. Earth air heat exchanger (EAHE), vertical ground source heat pump (VGSHP), and horizontal ground source heat pump (HGSHP) are evaluated from the viewpoint of environmental impact, performance, economy, and health. This study is the first study related to the evaluation of EAHE and GSHP systems by using the analytical hierarchy process (AHP). It is concluded that EAHE is the best option for refugee settlements;also EAHE is a healthier option for the COVID-19 pandemic.
ABSTRACT
The blind spot can be defined as the area around the vehicle where the driver cannot see through the mirrors without turning their head or taking their eyes off the road. Similar blind spots occur in energy policy. Blind spots can occur in forecasting economic development and creating policy documents. This study uncovers potential blind spots and controversies in the sustainability assessment of energy supply technologies. A composite sustainability index was constructed to compare district heating with four individual heating technologies—wood pellet boilers, natural gas boilers, solar collectors, and heat pumps. A total of 19 indicators were selected and grouped into four dimensions of sustainability—technical, environmental, economic, and social. The results reveal that district heating can compete with individual heating technologies in all dimensions of sustainability;however, a possible blind spot lies in evaluating environmental performance indicators of the different heating technologies. This study provides a novel decision-making tool that policy-makers could use to identify and avoid potential blind spots and uncertainties in energy policy at an early stage.
ABSTRACT
Energy consumption is steadily increasing with the ever-growing population, leading to a rise in global warming. Building energy consumption is one of the major sources of global warming, which can be controlled with renewable energy installations. This paper deals with an advanced evacuated hybrid solar photovoltaic–thermal collector (PVT) for simultaneous production of electricity and domestic hot water (DHW) with lower carbon emissions. Most PVT projects focus on increasing electricity production by cooling the photovoltaic (PV). However, in this research, increasing thermal efficiency is investigated through vacuum glass tube encapsulation. The required area for conventional unglazed PVT systems varies between 1.6–2 times of solar thermal collectors for similar thermal output. In the case of encapsulation, the required area can decrease by minimizing convective losses from the system. Surprisingly, the electrical efficiency was not decreased by encapsulating the PVT system. The performance of evacuated PVT is compared to glazed and unglazed PVTs, and the result shows a 40% increase in thermal performance with the proposed system. All three systems are simulated in ANSYS 18.1 (Canonsburg, PA, USA) at different mass flow rates and solar irradiance.
ABSTRACT
[...]these measures should be combined with other measures. [...]the paper Maintenance of Passive House Standard in the Light of Long-Term Study on Energy Use in a Prefabricated Lightweight Passive House in Central Europe [5] is an experimental study on different parameters: the orientation that maximizes heat gains from solar radiation, thermal insulation of partitions, heat provided by a geothermal heat pump, and a mechanical ventilation system with a heat exchanger. Since the science has spoken, politicians and citizens now need to do their part to achieve the shared goal of a more sustainable and energy efficient building sector.
ABSTRACT
The net greenhouse gas emissions need to become zero or even negative beyond 2050 to comply with the Paris Agreement and keep global warming well-below 1.5–2 °C with respect to pre-industrial levels [2]. [...]in the oxy-combustion systems, the combustion of the fuel takes place with pure oxygen rather than air, giving as a result a virtually pure CO2 stream due to the absence of nitrogen in the incoming comburent gas. [...]it is expected that energy demand grows strongly in the developing countries in coming decades, and therefore, about 70% of CCS development should be carried out in these regions in order to meet the long-term climate targets included in the 1.5–2 °C global emission scenario [2]. [...]progress in CCS deployment must be accelerated in developing countries. Rich nations need to provide developing regions with not only financial support to facilitate the transition to low-carbon economy but also the experience gained in successful large-scale operating projects to reduce costs and risks in future scaling up of CCS technologies in the developing countries.
ABSTRACT
Hierdie artikel is gebaseer op botteleringproses optimering deur deurlopende verbetering. n Gevallestudie is by maatskappy XYZ geloods. Die Ses Sigma Definieer, Meet, Ontleed, Verbeter, en Beheer metodologie het getoon dat die bottelering en doppie-opsit prosesse defekte by die drie sigma vlak lewer. Die 5 Hoekoms, Pareto-kaart, visgraatdiagram en Verskaffers, Insette, Prosesse, Uitsette, Kliente model het getoon dat los doppies (31.6%), lae opvulvlakke (29.2%) en leě bottels (28.9%) die vernaamste redes tot hoě kostes as gevolg van swak gehalte is. Die moniteringstelsel is ontwerp op die toegepaste wringkrag te meet, die doppie werkstuk status te monitor en die drankie temperatuur soos dit die hitteruiler verlaat te meet. Die verkoelingstelsel van die menger is ontwerp met n geslote lus beheerstelsel. As die drankie se temperatuur nie binne een of twee grade Celsius is nie, word dit gestuur vir sekondere verkoeling, anders beweeg dit aan. Die glikol inlaatklep word aangedryf sodat die vloei van die verkoelingsmiddel aangepas word om te verseker die primere verkoeling is doeltreffend. Die resultate toon dat dit moontlik is om die proses binne die ses sigma vlak te bedryf.Alternate :This paper is based on bottling process optimisation through continuous improvement. A case study was done at XYZ company. The Six Sigma Define, Measure, Analyze, Improve, and Control (DMAIC) methodology revealed that the bottling and capping processes were producing defects at 3 Sigma level. The 5 Whys, Pareto chart, fish bone diagram, and Suppliers, Inputs, Process, Outputs, Customers (SIPOC) model showed that loose-capped bottles (31.6%), under-fills (29.2%), and empty bottles (28.9%) caused the highest cost through poor quality. The monitoring system was designed to monitor the applied torque value, the capping head status, and the beverage temperature upon leaving the heat exchanger. The cooling system on the mix processor was designed using the closed loop control strategy. If the beverage temperature is not within 1 or 2 degrees Celsius, it is directed to secondary cooling;otherwise, it proceeds. The glycol inlet valve is actuated such that the flow of the coolant is adjusted to ensure that the primary cooling is efficient. The results show that it is possible to operate production within the Six Sigma level.
ABSTRACT
The use of Stirling-cycle-based heat pumps in high-temperature applications and waste heat recovery at an industrial scale is of increasing interest due to the promising role in producing thermal energy with zero CO2 emissions. This paper analyzes one such technology as developed by Olvondo Technology and installed at the pharmaceutical company AstraZeneca in Sweden. In this application, the heat pump used roughly equal amounts of waste heat and electricity and generated 500 kW of steam at 10 bar. To develop and widen the use of a high-performance high-temperature heat pump that is both economically and environmentally viable and attractive, various analysis tools such as exergy analysis and life cycle assessment (LCA) can be combined. The total cumulative exergy loss (TCExL) method used in this study determines total exergy losses caused throughout the life cycle of the heat pump. Moreover, an LCA study using SimaPro was conducted, which provides insight into the different emissions and the overall environmental footprint resulting from the construction, operation (for example, 1, 8, and 15 years), and decommissioning phases of the heat pump. The combined results were compared with those of a fossil fuel oil boiler (OB), a bio-oil boiler (BOB), a natural gas-fired boiler (NGB), and a biogas boiler (BGB).
ABSTRACT
Combating the COVID-19 pandemic has raised the demand for and disposal of personal protective equipment in the United States. This work proposes a novel waste personal protective equipment processing system that enables energy recovery through producing renewable fuels and other basic chemicals. Exergy analysis and environmental assessment through a detailed life cycle assessment approach are performed to evaluate the energy and environmental sustainability of the processing system. Given the environmental advantages in reducing 35.42% of total greenhouse gas emissions from the conventional incineration and 43.50% of total fossil fuel use from landfilling processes, the optimal number, sizes, and locations of establishing facilities within the proposed personal protective equipment processing system in New York State are then determined by an optimization-based site selection methodology, proposing to build two pre-processing facilities in New York County and Suffolk County and one integrated fast pyrolysis plant in Rockland County. Their optimal annual treatment capacities are 1,708 t/y, 8,000 t/y, and 9,028 t/y. The proposed optimal personal protective equipment processing system reduces 31.5% of total fossil fuel use and 35.04% of total greenhouse gas emissions compared to the personal protective equipment incineration process. It also avoids 41.52% and 47.64% of total natural land occupation from the personal protective equipment landfilling and incineration processes.