Greenhouse Space Research Articles

Spray performance simulation and experiment analysis of a greenhouse fixed-pipe twin-fluid cold fogger with different nozzle settings.

High-efficient pesticide application equipment for protected cultivation is scarce. In response, a fixed-pipe twin-fluid clod fogger (FTCF) was proposed as a potential solution. To investigate the optimal nozzle layout and spray performance, a computational fluid dynamics (CFD) model was used to study the airflow distribution and spray deposition of a FTCF with different nozzle settings using the Euler-Lagrange approach. Specifically, two piping configurations, middle-cross-inverted (MCI) and bilateral-malposed-opposite (BMO), were combined with three nozzle spacings (2 m, 3 m, 4 m) resulting in six nozzle settings. Additionally, a greenhouse spray trial was conducted to test the performance of FTCF with the selected nozzle settings and to validate the model. The simulation results revealed that MCI piping configuration exhibited a stronger airflow disturbance compared to BMO configuration, indicating a more significant air-guided effect in the MCI configuration. Combining this finding with the ground droplet distribution analysis of MCI piping configuration, it was observed that MCI-2 m had the lowest coefficient of variation (CV) for ground deposition (20.56%). Consequently, MCI-2 m was determined as the most optimal nozzle setting. Verification results demonstrated a high consistency between experimental and simulated spray deposition results. The FTCF system effectively generated a three-dimensional airflow field throughout the greenhouse environment. Furthermore, jet flow produced by FTCF disrupted the overall airflow pattern within the greenhouse space which facilitated droplet suspension and dispersion. This study provides valuable insights and innovative ideas for enhancing pesticide application technologies in protected cultivations. © 2024 Society of Chemical Industry.

Energy Efficient Building-Planning and Designing a Green and Cost-Effective House and Working Space for Farmer

Abstract: Agriculture in India is livelihood for a majority of the population and hence it stands great importance in Indian culture. Increasing population, increasing average income and globalization effects in India also increased the demand for quantity, quality and nutritious food, and variety of food. Therefore, pressure on decreasing available cultivable land to produce more quantity, variety and quality of food will keep on increasing. Farmers are still not able to earn respect a blearing. Therefore it is necessary to reduce this problem of them. The basic aim of this project is to plan, design a green and cost effective house and working space for farmer his family, shelter for his animals, proper grains to rage facilities and ware house for his tools and machineries. This project also provides an insight to overcome the water scarcity

MICROGRAVITY PLANT HABITAT –PHYSICAL AND ELECTRICAL PROTOTYPING

The article explores the intricacies of the "Microgravity Plant Habitat" through an in-depth investigation of its design, functionality, and implications for space exploration and colonization. Focusing on ongoing experiments like Veggie Plant Growth System, Advanced Plant Habitat (APH), and Space Greenhouse Experiments, the paper emphasizes the vital role of plant cultivation in supporting life, nutrition, and psychological well-being during deep space missions. The article proposes a novel solution to the challenge of water distribution in microgravity by introducing a modified aeroponics technique within a two-chambered module. This innovative approach ensures even water distribution, overcoming the complexities of gravity-free water droplet behavior. The Concept Article further details the parameters, experimental setup, and expected outcomes of the proposed system, highlighting its potential for reducing mission costs, conserving resources, and enhancing space habitability. The study contributes to advancements in space agriculture, aiming to create a sustainable and efficient system for plant growth in the unique environment of microgravity. The implications extend to the development of water management strategies critical for the success of future space exploration and habitation initiatives. The article concludes by proposing corrective measures and referencing relevant research to support ongoing efforts in space-based agriculture

‘Single-Seed-SpeedBulks:’ a protocol that combines ‘speed breeding’ with a cost-efficient modified single-seed descent method for rapid-generation-advancement in oat (Avena sativa L.)

BackgroundIn plant breeding, one of the most cost-effective and efficient ways to increase genetic gain is to reduce the breeding cycle time. In general, modern breeding methods for self-pollinated crops should strive to develop fixed lines at the lowest possible cost and in the minimum possible amount of time. Previous studies on spring oat (Avena sativa L.) showed that combining high plant density with limited soil fertility and moisture levels in a growth media like sand effectively decreases the time and cost of generating fixed single-seed descent lines. More recently, ‘speed breeding,’ or the exposure to prolonged photoperiod regimes of 22 h, has been shown to decrease flowering time in oat significantly. The goal of this study was to combine ‘speed breeding’ with high-density planting in a limited soil fertility media to reduce further the costs and time required to develop oat single-seed-descent lines.ResultsWe grew oat plants at low density in potting-mix (control), high density in potting-mix (HD-soil), and high density in sand (HD-sand) under 16 and 22 h of day length. We observed that oat plants grown in HD-sand and exposed to 22 h day length reduced their flowering time by around 20 and 5 days on average compared to those grown in control conditions at 16 and 22 h, respectively. We also observed that 85% of plants grown at high density in sand produced a single seed when grown in bulk conditions. In contrast, only 40% of plants grown at high density in potting-mix produced a single seed.ConclusionsOur novel protocol showed that oat plants grown in high-density bulks, using sand media and 22-hour day length, reduced their flowering time by 20 days compared to control conditions and produced plants with single seeds, following closely single-seed descent assumptions while significantly reducing labor costs and greenhouse space. This methodology can be deployed in oat breeding programs to help them accelerate their rate of genetic grain for multiple traits.

Techno-economic case study of applying heat recovery and CO2 capture systems on a gas turbine power plant; 4E analysis

Produced CO2 from fossil fuel-based transportation vehicles and energy systems can have a direct impact on people who live in adjacent of the power plants. So, in the present work, we proposed and modeled an integrated system comprising a gas engine, a carbon dioxide capturing unit, an absorption chiller, and a greenhouse. The greenhouse uses directly the CO2 produced in gas engine through the carbon dioxide capturing unit to mitigate the emitted CO2 into the atmosphere. Besides that, the produced heating in gas engine could be exerted in a cycle to render the greenhouse space in cold weather condition. In warm seasons this thermal energy could also be delivered to an absorption chiller for producing required cooling for inside space of the greenhouse. Herein, the generated electricity is sold to grid, and an economic analysis is brought about. To evaluate and estimate the system performance and interest of selling electricity, a mathematical function was applied. The results show that, during cold seasons, the maximum possible net interest is 800,000 $, and for warm seasons is 2,500,000 $. The maximum COP is also achieved by 1.007. Finally, the amount of CO2 emission rate is mitigated at least 50%.

Research on multi-sensor positioning and number identification method of greenhouse based on hall effect

Wireless sensors are becoming increasingly important in greenhouse automation. In order for wireless charging to be as effective and stable as possible, accurate spatial physical location information and sensor quantity information are essential. Consequently, identifying sensor location and quantity information has become a crucial step in the construction of a high-quality greenhouse wireless charging system. This paper suggests using the Hall effect for multi-sensor positioning and quantity identification to solve this issue. The multi-sensor greenhouse space with Hall elements is modeled physically in three dimensions, with theoretical research and equation development. A magnetic field simulation using Maxwell is conducted to compare the magnetic field for sensor localization in space, and the parameters of the designed 3D physical model is optimized based on the simulation. Comparative experiments on sensor positioning and quantity identification were also carried out, and the design parameters constructed the experimental verification platform. After that, numerous sets of experimental comparison data were collected to confirm the system's viability. Finally, the positioning experiment's error between the calculated and test values is 5 to 11 percent, and the number of the receivers can be accurately obtained based on the number of Hall voltage pulse responses. The concept of multi-sensor positioning and number identification based on the Hall effect serves as a model and a direction for future research on wireless charging in greenhouses and other environments.

Greenhouses in space: from intention to implementation

April 12 is Cosmonautics Day, International Day of Human Space Flight. This is a memorable date dedicated to the flight of the first cosmonaut of the planet, Yuri Alekseevich Gagarin, who became a symbol of the earthlings' dream come true. The All-Russian Research Institute of Vegetable Breeding and Seed Production (Federal State Budgetary Scientific Institution Federal Scientific Vegetable Center (FSBSI FSVC)), like a number of other academic institutions, from the beginning of space exploration, got involved in the work to solve the problem of developing food for astronauts and continues research to this day. In the embodiment of the ideas of K.E. Tsiolkovsky and S.P. Korolev on the creation of space greenhouses received a number of significant achievements in the Federal Scientific Vegetable Center, Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, Institute of Biochemical Physics N.M. Emanuel, SSC RF IBMP RAS and others. Varieties of vegetable crops have been created, tested and recommended for weightlessness conditions: radish, Chinese cabbage, dill, lettuce and other rapidly maturing plants. The variety of Chinese Vesnyanka cabbage has successfully passed biotechnical tests on the ground model of the Phytocycle-SD space conveyor greenhouse, during which good production and biochemical parameters were obtained. Russian scientists are conducting research on developing a technology for cultivating various vegetable plants under space flight conditions – in closed ecosystems (synergotrons), which can serve as the basis of life support systems during space flights, at space stations or in space habitats, where some conditions specific for ISS. Studies have been carried out to study tomato plants grown from seeds that have been under space flight conditions for a long time. As a result of the study, a statistically significant increase in the levels of ascorbic acid, polyphenols and carotenoids, the total antioxidant activity of tomato fruits compared to plants grown from control seeds (ground control) was found.

Temperature stabilization based on passive cooling technology in the initial design of an eco-friendly mini greenhouse

Greenhouses become one of the buildings where the cultivation of plants. The concept of environmentally friendly greenhouses is included in the current model of urban agriculture. The design of the greenhouse building concept is environmentally friendly by utilizing passive cooling technology. Passive cooling technology is used in this design to balance the temperature and humidity of the greenhouse through natural energy flow. The purpose of the research and design of this building is to investigate the temperature differences inside and outside the greenhouse space. The results of this study know that passive cooling with and without water greatly affects the temperature in the room. Passive cooling without water will produce hot temperatures in the room compared to passive cooling using water.

Experimental study of storage system of a solar water heater equipped with an innovative absorber spherical double-walled tank immersed in a phase change material

In commercial active solar water heaters, during the thermal charge process, water is continuously circulated between the collector and the tank. The water is heated in the collector and then stored in a tank whose surface is insulated. The shape of the collector and tank is an important factor in the development of solar thermal storage systems. In this study, the collector and tank are made spherical, fixed, symmetrical and capable of tracking the sun regardless of the placement angle. Also, in an innovative idea, the solar thermal storage tank is designed as a double-walled spherical tank. The water heated by the collector is stored in the inner chamber of the double-walled tank, and this chamber is surrounded by a Phase Change Material (PCM) by embedding the PCM in the outer chamber of the tank. Therefore, the PCM has the two roles of thermal insulation and thermal storage. As well as removing the thermal insulation, it is also possible to absorb solar energy on the external surface of the tank. To reduce heat losses, the tank is surrounded by a transparent glass cover in a greenhouse space. The maximum storage temperature and the maximum thermal efficiency in the thermal charge process are 80.3 °C and 74 %, respectively, which occur at a flow rate of 1.75 l/min. In this situation, the warm water needed by 8.43 people is produced. The greatest thermal stratification occurs at a flow rate of 1.25 l/min, and it weakens by raising the flow rate.

ПУТИ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ ИСПОЛЬЗОВАНИЯ ПОЧВОЗАМЕНИТЕЛЯ ПРИ ВЫРАЩИВАНИИ КОРНЕПЛОДНЫХ КУЛЬТУР В КОСМИЧЕСКОЙ ОРАНЖЕРЕЕ

The most promising method of root supply in space greenhouses (SG) operating in microgravity is porous membranes together with a capillary-porous salt-saturated artificial soil (AS). AS is a critical consumable that cannot be recycled in space missions. One of the options for increasing the specific harvest of cultures with extended period of commercial vegetation, carrot as an example, can co-cropping with fast-growing greens at the beginning of cultivation. Purpose of this work is experimental testing a technology of co-cropping carrot and leaf vegetables to see whether it will and better the AS efficiency. In a series of 3 experiments carrots were cultivated under a lighting unit with red and white LEDs (PFD in the range of 300 to 600 µmol(m2•s) in root modules stuffed with granular or fiber AS. Co-cultures were lettuce, Japanese turnip and basil. It was demonstrated that PFD at 450 – 550 µmol(m2•s) and water potential in the root zone at [(–0.5) – (–0.8) kPa] are favorable to the carrot and lie within the ranges recommended for cultivation of leaf vegetables in space greenhouses. No negative allelopathic effect was noted during carrot co-cropping with lettuce or Japanese turnip. Carrot cultivation with the Japanese turnip saved the specific, per a crop biomass unit, energy expenditure for lighting. Co-cropping with the Japanese turnip reduced the specific AS expenditure about 4 times; co-cropping with the lettuce reduced AS expenditure in 2.5 times.

Tissue culture coupled with a gas exchange system offers new perspectives on phenotyping the developmental biology of Solanum lycopersicum L. cv. 'MicroTom'.

Solanum lycopersicum L. cv. 'Microtom' (MicroTom) is a model organism with a relatively rapid life cycle, and wide library of genetic mutants available to study different aspects of plant development. Despite its small stature, conventional MicroTom research often requires expensive growth cabinets and/or expansive greenhouse space, limiting the number of experimental and control replications needed for experiments, and can render plants susceptible to pests and disease. Thus, alternative experimental approaches must be devised to reduce the footprint of experimental units and limit the occurrence problematic confounding variables. Here, tissue culture is presented as a powerful option for MicroTom research that can quell the complications associated with conventional MicroTom research methods. A previously established, non-invasive, analytical tissue culture system is used to compare in vitro and conventionally produced MicroTom by assessing photosynthesis, respiration, diurnal carbon gain, and fruit pigments. To our knowledge, this is the first publication that measures in vitro MicroTom fruit pigments and compares diurnal photosynthetic/respiration responses to abiotic factors between in vitro and ex vitro MicroTom. Comparable trends would validate tissue culture as a new benchmark method in MicroTom research, as it is like Arabidopsis, allowing replicable, statistically valid, high throughput genotyping and selective phenotyping experiments. Combining the model plant MicroTom with advanced tissue culture methods makes it possible to study bonsai-style MicroTom responses to light, temperature, and atmospheric stimuli in the absence of confounding abiotic stress factors that would otherwise be unachievable using conventional methods.

Minimization of the equivalent system mass of a vitamin greenhouse with LED lighting for various scenarios of space missions

To improve the habitat of the manned spacecraft (MS) crews with fresh vitamin greens, relatively small and economical space greenhouses (SG) with LED-based lamps (LED) can be used. In order to reduce the costs of onboard resources when growing plants in SG, the method of adaptive search optimization of the lighting parameters of plants during their growth was used. The minimum specific value of the light-dependent part of the equivalent system mass (ESM) per unit of grown biomass (G) was used as the current optimization criterion for SG. The current value of the criterion at plant age t during period of time Δt can be written as: min G (I, t, Δt) = min{[Cv (k3/k2) + CE (k4/k2)·I]/F(I,t) Δt}. Here F(I,t) - is the current net photosynthesis of the crop; CV,CE – cost factors of consumed by SG electric power unit and unit of volume occupied by the SG, in kg/m2 and kg/kW, respectively; k2-k4 - constants of dimension matching; I – lighting attributes which include combination of parameters (intensity, spectrum, time distribution). If lighting spectrum and time distribution are constant, I will equal to average PPFD. Obviously, the cost coefficients CV, СE can depend both on spacecraft design and on space mission specificity – flight duration, task program, crew number, etc. The CV and CE have been calculated for 3 published scenarios of space missions: for a manned station in low Earth orbit, a planetary mission on a Lunar base and a planetary mission on Mars. Special stand was built for adaptive optimization of crop illumination using the crop net photosynthesis as biofeedback. Chinese cabbage was grown in a phytotron under 24-h lighting per day. Above the crop, an LED lamp was mounted with autonomous regulation of supply currents for LEDs with red (660 nm) and white (color temperature 4000 K) radiation. The crop net photosynthesis was automatically measured every 15 min by the rate of CO2 decrease in the closed phytotron air. The control software and hardware complex calculated the value of the optimality criterion G (t) at the time of measurement and calculated the optimal parameters of the supply currents for red and white LEDs, which were implemented at the next iteration of the search. The optimal lighting dynamics for Chinese cabbage crop in the phytotron, minimizing ESM, was experimentally obtained for the last 7 days of the plants’ growth.

Crop-local CO2 enrichment improves strawberry yield and fuel use efficiency in protected cultivations

In protected strawberry (Fragaria × ananassa Duch.) cultivation, CO2 enrichment is essential to enhance both fruit quality and yield. Fuel burning generators are commonly used to supply CO2 to entire commercial greenhouse space. However, methods that are less fuel-based are desired for contemporary agricultural practices. A new crop-local CO2 enrichment system using a modified fuel-burning generator has been developed to increase yields and decrease the fuel required for CO2 enrichment in greenhouse strawberry production. This crop-local CO2 enrichment (CLC) method directly supplies CO2 from perforated tubes set in the interrow space of the plant canopy. The effects of this technique on fruit quality, fruit yield, and fuel use efficiency have been examined in comparison with conventional CO2 enrichment (CC) practices. The CLC method increased CO2 concentration inside the plant canopy by 100–200 μmol mol–1 when compared with CC under the ventilating conditions by a roof window. This resulted in significant increases of approximately 10–26% in the average fruit weight, 13% in the cumulative fruit number, and 22% in cumulative marketable yield when compared to CC. Furthermore, cumulative fuel consumption was approximately 27% lower with the CLC method when compared to CC. These results indicate that CLC improves fuel use efficiency when compared with CC as it increased yields and decreased fuel consumption.

Fuzzy Method Design for IoT-Based Mushroom Greenhouse Controlling

The ideal conditions for the oyster mushrooms growth are at a humidity of 65-75% and 29-31C during incubation, while the growth of stems should be at a humidity of 70-90% 29-32C. This ideal ecosystem is maintained by aeration and manual watering. Still, the results are not optimal in preventing damage to the mycelium during the incubation period, resulting in a decrease in crop yields. Automatic control has not created ideal conditions because air temperature and humidity regulation are only based on fans and sprayers that do not directly affect air conditions. Therefore, we need a method to manipulate the mushroom greenhouse space ecosystem, namely fuzzy logic, the application of fuzzy logic integrated with sensors, actuators, and microcontrollers with the Internet of Things to solve this problem. The results of the installation of fuzzy logic in the mushroom's greenhouse in this system can be seen from the fan's modulation response and the pump's duration. The test results of this control feature can manipulate temperature and humidity. Therefore, the oyster mushroom greenhouse produces an ideal state of 29.8C, the humidity of 68.97% RH, and the production has been proven to be optimal with an average daily harvest of 3.8kg.

Crew time in a space greenhouse using data from analog missions and Veggie

Crew time requirements for human space exploration missions is as critical as mass, energy, and volume requirements. However, it has only been sporadically recorded in past analog and space missions for plant cultivation. In this retrospective study on crew time data collected in various analog facilities and on the Veggie hardware on ISS, we propose a methodology for efficient categorizing and reporting of crew time in space plant growth systems. Crew time is difficult to capture in operational environments, and this study intends to harmonize these efforts among different locations. This article also provides a current database for required crew time in several plant growth hardware and facilities, on the ISS, and on Earth. These data could serve mission planners as a baseline to establish standardized activities and extrapolate crew time needed to operate future plant growth units. Finally, we discuss how crew time needed for plant cultivation will change in future exploration missions, based on choices made for plant species, watering systems, level of automation, and use of virtual assistants, among others. Crew time will need to be accounted for as a decisive factor to design future space greenhouse modules.

Production cost analysis of organic and conventional vegetable seedlings

This study investigated the economic differences between organic and conventional seedling production of vegetables in Louisiana (US) during 2018. Broccoli, cabbage, and cauliflower organic and conventional seeds were used. Cost analysis was conducted for organic and conventional seedling production, including trays, containers (100 count flats), seeds, substrate, fertilizers, water used for fertilizer treatment, and irrigating the crop, labour, and greenhouse space utilized. Calculations were based on total production cost and net returns for 1 flat, 100 flats, for the production of 100 flats in 3 repetitions, and for the space of 100 m² in the greenhouse. After seedlings reached suitable growth for transplanting, a survey was conducted to determine potential demand for the production of organic and conventional vegetable seedlings for home gardeners. The total production cost of one plant/repetition equated to organic broccoli $0.31, organic cabbage $0.26, and organic cauliflower $0.30, whereas conventional seedlings equated to broccoli $0.15, cabbage $0.11, cauliflower $0.16. The net returns in the production of conventional seedlings for 100 flats 3x per year for broccoli $2,808.1, cabbage $3,498.1, cauliflower $2,760.7 was higher compared to organic seedlings: broccoli $1,201.01 (57.2 % lower than conventional), cabbage $2,118.06 (39.4% lower than conventional), cauliflower $1,572.1 (43 % lower than conventional). In the production of seedlings per 100 m², net returns were almost doubled for conventional seedlings compared to organic seedlings. Despite needing to recoup higher costs for organic vegetable transplants, more Louisiana consumers (65 %) prefer to pay a higher price to buy organic vegetable seedlings compared to conventional vegetable seedlings.

Разработка модульного программно-аппаратного комплекса управления стендом с моделью космической оранжереи

Space greenhouses (SG) that can be used for enriching the astronauts’ diet are also considered a means of improving the astronauts’ life environment in autonomous crewed expeditions. One of the main requirements for SC is to minimize the specific consumption of the main onboard resources: energy, space, refrigerant, and labor-hours per unit mass of grown product. Experiments on adaptive optimization of irradiation and illumination spectrum were performed and a hardware and software complex (HSC) was developed to control the test-stand with the SG model. The main object of control is an intermittently pressure-sealed chamber with temperature and humidity sensors, as well as an IR gas analyzer. The latter determines the visible photosynthesis of the plants based on the dynamics of CO2 absorption. The sensors and actuators are connected to a Mega 2560 AVR microcontroller connected to a Raspberry Pi 4B single-board computer via a USB-UART converter. The modular software package was created on the basis of the ROS (Robot Operating System) framework, which minimizes the training period for new developers and experiment operators. The first HSC versions were successfully tested on a test-stand with Chinese cabbage to find the trajectory of optimal lighting parameters during the growth process. The HSC made it possible to carry out several replications of a 2-factor experiment to study the drift of the optimal LED lighting modes during a 10 days’ period with daily variation of 2 factors — the current in the red LED circuit and the current in the white LED circuit. Optimal change patterns in the lighting parameters for a test-stand with a space greenhouse model were obtained.

Automated diseases detection of plant diseases in space greenhouses

To detect plant diseases in a space greenhouse, a computer vision method is proposed by counting image pixels in the space of color channels of red, green and blue. An algorithm and a program have been developed for the automated determination of the degree of fungal diseases affecting garden strawberry leaves from the transmitted images of plant leaves. The research results can be used for early diagnosis of diseases and monitoring of the functional state of greenhouse plants.

Internode elongation and strobili production of Humulus lupulus cultivars in response to local strain sensing

Three different cultivars of Humulus lupulus L. were subjected to a regime of internode touch and bending under greenhouse conditions. Experiments were performed to assess intraspecific variability in plant mechanosensing, flower quality, and yield to quantify the thigmomorphogenic impact on plant compactness and flowering performance. Touching and/or touching plus bending the plant shoot internodes located in the apical meristem zone decreased internode elongation and increased width. The growth responses were due partly to touching and/or touching plus bending perturbation, 25.6% and 28% respectively. Growth of new tissue within the local apical portion of the bine continued to remain mechanosensitive. The number of nodes and female flowers produced was unaffected by either type of mechanical stress. The study provides evidence that thigmomorphogenic cues can be used as a hop crop management tool to increase bine compactness and increase node density per unit area. The findings have broad implications for hop production; production can more readily take place in a confined greenhouse space with the aid of mechanical stimulation to control plant growth without sacrificing yield or flower quality.

Energy cost and efficiency analysis of greenhouse heating system enhancement using phase change material: An experimental study

The growing production of greenhouse gases and fossil fuels price obligated decision-makers in communications to implement energy sources more efficiently. The greenhouses have been developed through the years for the safe production of food sources. Thermal energy devotes a large portion of energy need in greenhouses. In developing countries, the rate of fuel consumption in the greenhouse is high, and there is an urgent need for improving heating systems. Here the possibility of reusing and storing the waste heat by phase change material (PCM) in a sample greenhouse studied experimentally. The PCM heat recovery system (PCM HRS) is a20cm×50cm×140cm plate type heat exchanger where the plates are replaced with PCM plate containers. The charge and discharge of the system are performed in two separate sections. The discharge stage organized in two separate schemes: delivering the stored heat directly inside the greenhouse space and using stored heat to preheat the combustion air of the burner. The heating system analyzed from the viewpoint of energy and the results show that the effect of preheating the heater air gives rise to a 23.7% reduction of gas consumption and the effect is much more pronounced compared to the direct using of the stored heat. Also, the resulted energy saving obtained by using the PCM HRS returns the initial investment within four months.