الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 191 |  |  |
| | | from | 191 | | |
Abstract
An evaporative pad cooling system is one of the most efficient cooling techniques for controlling the temperature and humidity inside a greenhouse. The fan-pad system (FPS) is a type of DEC; its simple construction and operation have led to widespread use for greenhouse cooling. It aims at reducing dry inlet temperature. The reduction in dry bulb temperature is due to extracting heat from the dry air by evaporation. Evaporation is done by both heat and air velocity to release the water from pad surfaces The objectives of the present research may be mentioned as follows: the objectives of this study were to: Study the feasibility of using the evaporative pad fan cooling system in mushroom housing, study some engineering parameters affecting cooling system performance such as (pad water flow rate, extraction fan velocity, setting temperature, and two different pad materials), determine the most suitable water flow rate, fan air velocity and setting the temperature for operating the two different pad materials (Luffa and Cellulose), increasing mushroom production and increase the economic benefits from mushroom production. Experimentation The experimental work was carried out on the roof of the Faculty of Agriculture, Tanta University, in the Gharbyia Governorate of Egypt (Φ is 30.49° N, 30.59° E), in February 2021. Two identical Mushroom houses were tested in the experiments. The geometric dimension for each house was as follows, 2.6 m in length, 1.5 m in width, and 1.5 m in height, and had a floor surface area of 3.9 m2 and a volume of 5.85m3. The first house (A) has an a-cellulose pad as a cooling medium and the second house (B) has Luffa as a cooling medium. Experimental set up In the experiments, the FPCS was operated during the Oyster Mushroom fruiting initiation stage, which is approximately 1 month and can tolerate temperatures up to 28-32°C. The FPCS was set to run during the day and shut down at night because the temperature was in the acceptable range then. The air relative humidity would increase during FPCS operation and thus be sufficient for Oyster mycelium growth. The experiment was done in two parts, first the pre-experiment, in this part different treatments were taken into consideration such as air temperature, fan air velocity, and water flow rate when using cellulose and Luffa as pad material. The second part of the experiment was planting the mushroom using the optimal treatment air temperature, pad face air velocity, and water flow rate in the case of using cellulose and Luffa as pad materiel. Pr -experiment Some operational parameters were taken into consideration such as air temperature (28 and 32 ºC), fan air velocity (1.3, 1.8 and 2.5 ms-1), and water flow rate (4.2, 6 and 8 Lmin-1) when using cellulose and Luffa as a pad material. The second part of the experiment was planting the mushroom using the optimal treatment air temperature, pad face air velocity, and water flow rate in the case of using cellulose and Luffa as pad materiel Experimental procedure Experimental work was done in two similar mushroom houses during the summer of 2021 using fan- pad cooling system using a fan air velocity of (1.3 m/s), a water flow rate of ( 4.2 L. min -1) and a set temperature of 28ºC for cellulose pad and Luffa pad The comparison study between the two types of pad materials was set depending on the efficiency indicators of the selected pad in the form of cooling effect, saturation efficiency, heat energy removal, water consumption on evaporation, evaporative cooling performance and ratio of temperature reduction to airflow rate (T/Q) and mushroom production. The selected fan air velocity and the water flow rate were done according to the pre-experiments results. 12 kg of straw are soaked in 200 liters of dissolved water in which 2.5 kg of slaked lime is for 24 hours, then dried for 48 hours, then half a kilo of seeds (spawn or grain/mycelium) is planted. The main component of the (Pleurotus ostreatus) was pasteurized straw packed in clear plastic bags with a diameter of 40 cm and a height of 60 cm with 6 kg in mass. The bags of compost were inoculated with spawn or grain/mycelium mixture and were placed on shelves in the mushroom house. The bags were vacuumed of air and tight well. The incubation period lasts for 2 weeks at a temperature of 25 °C. Before the fruiting stage, the bags were punched to allow for fruit to grow up. The humidity level inside the bags ranges from 80 to 90% by using a fog pump, which was operated automatically for 3 min every hour and the air temperature ranged between 20 to 30°C. The water pump withdraws water from the water tank through a filter and then pumps it through a perforated distribution pipe above the pads. . A gutter under the places was used to hold the water draining from the pads. The collected water can be recycled as long as salt or minerals do not accumulate on the pads. A valve was used to adjust the water flow rate through the distribution pipe. Measurements 1. Temperature measurements and relative humidity 2. Air velocity 3. Water flow rate 4. Air flow rate 5. Mushroom Measurements The mushroom measurement parameters were the stalk height (cm), cap diameter (cm), individual weight (g) and the number of fruiting bodies, temperature, and moisture content of the substrate. The fresh weight was measured with a digital balance. Important results The important results of the present study can be summarized as follows: 1-This comparison indicated that under 28 °C and using different water flow rates with 1.3 m/s as air velocity the maximum inside air temperature with luffa pad material gave values lower than cellulose pad material. 2-Moreover, the minimum value of water flow rate (4.2 L/min) and minimum air velocity (1.3 m/s) gave a higher cooling effect in most treatments. The contact time between water and air influences the performance of the system, minimum water flow rate plus minimum air velocity considers the interaction that causes best indicators, especially in the short distance between pad and fan as it happened in this present study. 3-In all treatments the values of saturation efficiency with 1.3 m/s were highest than other air velocity values, except with 32°C as adjusted temperature and 6 L/min. In addition, the lower values appeared with 2.5 m/s air velocity. Moreover, luffa pad material gave values of saturation efficiency higher than cellulose pad material. 4- The highest average value of saturation efficiency of about 92.22 % was achieved using pad of Luffa with 1.3 m/s pad face air velocity 4.2 L/min pad water flow rate and setting temperature of 28°C. 5- Providing indoor temperature and relative humidity around the required level helps in increasing biological efficiency by 79.17% 6- The mushroom yields were substantially higher in the cooling system unit using Luffa as pad martial (17.2 kg ) than that using Cellulose ( 9.6 kg) with an increasing percentage of 79.16 %. 7-Consequently, the estimated return profit was $ 131.67 (USD), which represents 78.69 % of the total income per operation. Using Luffa as a pad material increases the return of a profit by 189.48 %. pad was 11.83 (USA) CelluloseData showed that the operating cost of a -8$/kg meanwhile, Luffa pad was 7.31 (USA) $/kg. It was less for the Luffa pad than the cellulose pad. The criterion cost of the Cellulose pad was 31.28 (USA) $/kg while it was 17.045 (USA) $/kg in the case of using the Luffa pad 8-However, if cellulose is employed as pad material, the operational costs will increase. from the results mentioned above, using Luffa as pad material in the cooling system reduces the consumption of electrical energy by 16.66 %. This stark reduction is very important in cases of energy reduction costs. from an economic point of view, the production of mushrooms is promising for supplying the anticipated demand for them. 9- Using Luffa fibers as pad material in an evaporative cooling system may be feasible. This can solve the expensive of cellulose pad material. from the previous results, it may be recommended the following: 1-The best water pad flow rate, extraction fan air velocity, and setting the temperature for operating cooling systems (Luffa and cellulose ) are 4.2 L.min-1,1.3 ms-1, and 28 °C respectively. 2-Using Luffa in a pad and fan evaporative cooling system is feasible for the mushroom house from an environmental and economic point of view.