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Portion of the heated greenhouses, heat distribution system, and fuels used in a the Leverano greenhouse district and b the Taviano greenhouse district
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Greenhouse farming, where energy consumptions are mainly related to the greenhouses heating, is one of the sectors consuming the most energy in the agricultural industry. High costs and the uncertain availability of fossil fuels constrain the use of heating applications. Among possible solutions, the utilization of renewable heating systems such as...
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... However, GSHPs have been recommended as an affordable HVAC system for industrial poultry production in China [136]. Overall, comparative studies between GSHPs and ASHPs concluded that GSHPs are more costly than ASHPs (e.g., [137][138][139]). The payback period range was extensive across the reviewed studies. ...
Egg production is amongst the most rapidly expanding livestock sectors worldwide. A large share of non-renewable energy use in egg production is due to the operation of heating, ventilation, and air conditioning (HVAC) systems. Reducing energy use, therefore, is essential to decreasing the environmental impacts of intensive egg production. This review identifies market-ready alternatives (such as heat pumps and earth–air heat exchangers) to traditional HVAC systems that could be applied in the industrial egg sector, specifically focusing on their use in temperate and continental climates. For this analysis, energy simulations were run to estimate the typical thermal loads of caged and free-run poultry housing systems in various Canadian locations, which were used as examples of temperate and continental climates. These estimations were then used to evaluate alternative HVAC systems for (1) their capability to meet the energy demands of egg production facilities, (2) their environmental impact mitigation potential, and (3) their relative affordability by considering the insights from a systematic review of 225 relevant papers. The results highlighted that future research should prioritize earth–air heat exchangers as a complementary system and ground source heat pumps as a stand-alone system to reduce the impacts associated with conventional HVAC system operation in egg production.
... The heat gain from solar radiation, denoted by Q sr , is a function of solar intensity, greenhouse area, and the transparency of the covering material. This quantity is expressed by Eq. (1) and represents the amount of heat gained from short solar radiation [24]. ...
This paper introduces a comparative study of four distinct controllers intended for efficient temperature regulation in smart greenhouses. Beginning with an overview of the general research background, the paper addresses the specific challenges inherent in greenhouse temperature control, as well as the different techniques used for regulation. Utilizing Matlab Simulink software, the greenhouse temperature control system is simulated. The study evaluates the performance of each controller in maintaining the internal temperature within the desired range amidst varying external conditions. Previous research has shown that all four controllers effectively maintain the desired temperature range, although their performance varies in terms of power consumption, precision, robustness, and response time, depending primarily on the project requirements and goals. Our contribution primarily consists of studying all these types of controllers and determining the best controller to choose for regulating the internal temperature of the greenhouse.
... D'Arpa et al. investigated the cost-effectiveness of geothermal heat pumps for heating greenhouses in Southern Italy based on greenhouse models and a survey made with operators. They concluded that horizontal and vertical ground-coupled heat pumps could be economically viable in such areas [20]. Finally, Nawalany et al. numerically simulated a 456 m 2 greenhouse located in Poland. ...
... Equation (18) provides the water mass flow rate from the zone air toward wall i (in kg/h). Water condensation depends on the actual vapor pressure in the zone air (E a in kPa) and the saturation vapor pressure at the inner side layer temperature T i (E o (T i ) in kPa), both provided by Equations (19) and (20). A i is the considered wall area, and H in,i is the convection heat transfer coefficient of the wall's inner side (in kJ/h/m 2 /K) [23]. ...
Communities operating urban greenhouses need affordable solutions to reduce their heating consumption. The objective of this study was to compare the ability of different simple ground-based solutions to reduce the heating energy consumption of relatively small urban greenhouses operated all year round in a cold climate. An urban greenhouse located in Montreal (Canada) and its thermal interactions with the ground were modeled with the TRNSYS 18 software. The following greenhouse scenarios were simulated: partially insulating the walls, partially burying the greenhouse below the ground level, reducing the inside setpoint temperature, and using an air–soil heat exchanger (ASHE) or a ground-coupled heat pump (GCHP). The heat exchangers for the last two cases were assumed to be located underneath the greenhouse to minimize footprint. The results showed that reducing the setpoint temperature by 10 °C and burying the greenhouse 2 m below the surface has the most impact on fuel consumption (−33% to −53%), while geothermal systems with a limited footprint (ASHE and GCHP) can reduce the fuel consumption by 21–35% and 18–27%, respectively, depending on the soil thermal conductivity and ground heat injection during summer. The scenarios do not provide the same benefits and have different implications on solar radiation availability, growth temperature, electrical consumption, and operation that must be considered when selecting a proper solution.
... However, the balance between the agronomic needs of plants and the energy-saving potential of each heating technique requires attention as well [2]. Among the energy-saving potential that renewable and sustainable solutions (e.g., photovoltaic modules, solar thermal collectors, wood pellet, …) also heat pumps (HP), have found interest for greenhouse systems, but only in the case of geothermal source heat pumps, integrated systems [3][4][5]. There are many reasons, mostly deriving from traditional design in building experiences, why HP hasn't found great interest in protected agriculture applications. ...
Protected horticulture is a highly energy-consuming sector where optimizing energy use and cost for heating facilities is strategic to achieve high environmental and economic sustainability. The paper main aim is to present the use of a heat pump (HP) for basal heating as an alternative technology to produce bedding plants. The experimental test was carried out by bedding plant production for the early spring market. The adopted greenhouse, located in Tuscany, Central Italy, consisted of a frame made of galvanized iron, roofing in polycarbonate slabs, and walls of polyethylene sheets with a fully automatized opening system equipped with twelve concrete benches.The benches were isolated from the ground with polystyrene and a substrate of volcanic lapilli. Then eight benches were provided with a basal heating system based on four couples of coaxial pipes circulating warm water, while four were not heated. Cuttings of Impatiens Walleriana ‘Buddha F1 Carmine’ were transplanted in 1.2 L pots and subsequently grown by comparing basal heating of 16 °C with no basal heating conditions for a total of 960 potted plants. According to requirements, all the plants underwent the same agronomic care (fertigation and pest control). The microclimatic conditions and the energy consumption were acquired. The experimental results show that the heat pump ensures suitable thermal conditions for such cultivation in the winter period, confirming the possibility of using a conventional heat pump in horticulture as a simple installation in an existing Mediterranean greenhouse.KeywordsEnergy savingefficiencygreenhousecontrolled environmenthorticulture
... In this framework, agricultural greenhouses represent an important source of the energy demand, resulting in their being one of the higher energy-consuming sectors in farming [8]. Heating accounts for 70/85% of the total energy consumption as one of the largest operating costs for the maintenance of a greenhouse, after labour and plant materials [9,10]. ...
Generally, greenhouses are high energy-consuming, sometimes accounting for 50% of the cost of greenhouse production. Geothermal energy plays a very important role in maintaining the desired temperature and reducing energy consumption. This work deals with a project of a hybrid heating plant (97% geothermal energy and 3% gas-condensing boiler) for the innovative Plant Phenotyping Greenhouse at the University Campus in Grugliasco (few km West of the city of Turin). The aim of the study is to testify to the energy efficiency of this kind of hybrid plant as well as its economic sustainability. Numerical simulations of a GRT were used to calibrate the system and verify that the software reasonably modeled the real case. They helped to correctly size the geothermal plant, also providing data about the thermal energy storage and production during on and off plant cycles. The results show a thermal power of 50.92 kW over 120 days of plant operation, in line with the expected energy needs to meet the base load demand. Long-term results further ensure a negligeable impact on the ground, with a thermal plume between 5 and 10 m from the plant, reducing substantially in a few months after switching off the plant.
... Rights reserved. less primary energy consumption compared to that of a conventional heating and cooling system (D'Arpa et al., 2016;Michopoulos et al., 2013). ...
Temperature control with conserving nutrients and irrigation water reduces energy loss, leading to economic and sustainable greenhouse farming. A subirrigation system was applied to strawberry cultivation by placing tubes containing temperature-controlled water (obtained using heat pumps with air or geothermal heat sources) under the soilless substrate of a cultivation container. A ball tap supplied water gravitationally, avoiding the need for a water reservoir, thereby minimizing the volume of water required for heating and cooling. The substrate temperature in the heat pump treatments retained an optimal temperature for growth (averaging 18.4 ℃ in all seasons). The coefficient of performance of the heat pump with the geothermal heat source during heating operations was approximately 1.8 times higher than that with the air heat source. However, the geothermal heat source reduced overall electricity consumption by 14.9% for five months of the experimental period. Production was increased by 21% and 36% in the geothermal and air-source heat pump treatments, respectively, compared to that of the control, owing to the preferable condition of the substrate for strawberry growth. Although salinization of the substrate due to the closed irrigation system may be of concern and damage plant growth, the subirrigation system minimized the loss of water, nutrients, and heat owing to the omission of a reservoir. Furthermore, with minor modifications, the proposed system could be converted to a dual heat pump system to enhance energy use efficiency.
... The advantage of heat pumps is the possibility of heating or cooling the GH, depending on the current requirements of the facility. The application of heat pumps is conditioned by the availability of a lower heat source at appropriate parameters [6,7]. Another option is to power the GH with a cogeneration unit, which and environmental point of view was found to be significantly high when surveying several greenhouse locations in Europe [15]. ...
The paper describes the influence of horticultural production in greenhouses under Polish climate conditions on energy consumption, contributing to greenhouse gas emissions and global warming. Four scenarios were studied, two of which were non-renewable fuels: coal and natural gas, while the other two were renewable energy sources: wood pellets and wood chips, to identify opportunities for reducing energy costs and greenhouse gas emissions. Cumulative energy demand was defined to assess these four scenarios. The environmental impact was determined using the carbon footprint of the principal greenhouse gases emitted and using CO2 as the reference gas (CO2-equivalents). Renewable energy sources in greenhouse production can reduce the cumulative energy demand by 83.3% and greenhouse gas emissions by 95% compared to the coal-burning scenario. The presented research results relate to a greenhouse intended for growing flowers in pots, which has not been conducted so far. The article also updates the data on the environmental impact of crops grown in greenhouses located in Poland. The study provides important information for horticultural producers, mainly due to increasing competition and consumer awareness of the origin of products. Renewable energy sources in horticulture reveal a great potential in the reduction in greenhouse gases, and thus may become an inspiration to look for new solutions in this area.
... Heat pump technology (e.g., air source heat pump, ground source heat pump, and solar-assisted heat pump) is both a renewable and an energy efficient technology for both sanitary hot water and space heating [1], [2]. Extensive studies by a group of researchers in the United Kingdom have resulted in the finding that, air-source and geothermal heat pump water heaters can be employed in wider applications [3]. ...
The implementation of an energy efficiency intervention in the students' residence of the university campus may lead to a reduction in the energy consumed and electricity cost. The study focused on retrofitting a 1000 L, 12 kW boiler, with a 4.0 kW Air Source Heat Pump (ASHP) unit. A data acquisition system was built and deployed, to monitor the baseline performance of the electric boiler and the actual performance of the installed ASHP water heater (which was used to retrofit the electric boiler during the assessment period). The results show an annual electrical energy saving of 34805.94 kWh and load factor reduction of 0.124 due to the replacement of the electric boiler with the ASHP unit. The payback period of the ASHP system was 1.7 years, using the method of net present value of money. Wilcoxon rank sum test was employed to compare both the daily volume of water and energy consumed by the electric boiler and the ASHP water heater to test if their difference was of any significance. We concluded that, there exists a significant difference in the average daily energy consumed by the boiler and the ASHP water heater in both summer and winter season with the utilization of the Wilcoxon rank sum test. We could conclude that, a rollout of the ASHP units to retrofit the existing electric boiler in the students' residence in the University campus is economically viable and calls for such an intervention is imperative.
... Greenhouse energy consumption, especially for artificial cooling and heating or for lighting, is very high [7]. The use of renewable energy sources as replacement to conventional resources (fossil fuels) Such as solar thermal collectors, photovoltaic (PV) systems, thermal photovoltaic (PVT) systems, geothermal and biomass can reduce greenhouse production costs and help preserve the fossil reserves [8,9]. A clean, efficient power and heat generation system for greenhouse purposes is the photovoltaic (PV) system that directly convert solar energy to electricity [10]. ...
Greenhouses consume huge amounts of energy in cool seasons and the destructive effect of it has recently given rise to the popularity of renewable energies such as solar energy in greenhouses. A photovoltaic/thermal system was numerically simulated in ANSYS Fluent to be used in the design and development of an optimized structure of such a system. The system was simulated in three tube arrangement (continuous, longitudinal, lateral), 5 tube diameters (6, 8, 10, 12, 14 mm), and 7 flow rates (3, 2.75, 2.5, 2.25, 2, 1.75, 1.5 lit/min). The optimized design from the simulations was developed, and was tested in indoor and outdoor conditions of a greenhouse. The performance of both settings was compared under similar conditions. Simulation results revealed that the best design among the proposed scenarios for development of a thermal collector was the one with longitudinal 14 mm tubes under 3 lit/min flow rate. The results showed that there is a good agreement between field data and simulation data. It was also found that the mean electrical efficiency for the inside and outside systems was 9.72% and 5.28%, respectively. The thermal efficiency of the outside system was 58.15% whereas the efficiency of the inside system was 48.82%.
... As mentioned in many studies, the highest energy consumption and the largest source of environmental impact for greenhouse crop production is accounted for by its heating and cooling systems [6][7][8]. However, there have been very few studies related to environmental impact assessment of heating and cooling systems in greenhouses since published papers usually relate heating and cooling systems to residential, commercial or industrial buildings and other applications [9][10][11][12]. ...
A substantial reduction in the environmental impacts related to the construction and operation of agricultural buildings is needed to adapt to the continuing development of agriculture. The life cycle assessment (LCA) is a methodology used to quantify the environmental impact of different processes involved in the production and therefore has been increasingly applied to assess the environmental burden. However, most LCA-related research studies have focused on the overall environmental impact of the entire system without considering the energy load of the agricultural buildings. By integrating the LCA tool with other design tools such as the building energy simulation (BES), the identification of environmental hotspots and the mitigation options become possible during the design process. Thus, the objective of the paper was to identify the current integration approaches used to combine BES and LCA results to assess the environmental impact of different heating systems such as absorption heat pump (AHP) using energy from thermal effluent, electricity-powered heat pump and kerosene-powered boilers used in a conventional multi-span Korean greenhouse. The assessment result revealed that the environmental impact caused using a kerosene-powered boiler is largest in terms of the acidification potential (AP), global warming potential (GWP) and Eutrophication Potential (EP) of 1.15 × 100 kg SO2-eq, 1.13 × 102 kg CO2-eq and 1.62 × 10−1 kg PO4-eq, respectively. Detailed analysis of the result showed that the main contributor for greenhouse gas emission was caused by the type, amount and source of energy used to heat the greenhouse, which contributed to a maximum of 86.59% for case 1, 96.69% for case 2 and a maximum of 96.47% for case 3, depending on the type of greenhouse gas being considered.