M. Rural et at: A Confrolled Environmem Agriculture Greenluntse for the Caribbean Region

M. Rural et at: A Confrolled Environmem Agriculture Greenluntse for the Caribbean Region 10 ISSN 0511-5728 The West Indian Journal of Engineering Vol.40. No.2. January/February 20I8. pp.10-16 A Controlled Environment Agriculture Greenhouse for the Caribbean Region Maria Suraj Edwin I. Ekwue "•'", and Robert A. Birch' Department of Mechanical and Manufacturing Engineering. Faculty of Engineering. The University of the West Indies. St. Augustine. Tr' dies: "E-mail: 'E-mail: Corresponding Author (Received 28 June 2017; Revised 24 November 2017; 05 December 2017) Abstract: A prototype Controlled Environment Agriculture (CEA) greenhouse, designed to suit the climatic conditions of Trinidad and Tobago was constructed and tested alongside a non-controlled prototype greenhouse with natural ventilation. In the CEA greenhouse, fan and pad type evaporative cooling were used to reduce temperature; circulating air combined with natural ventilation to reduce the humidity and provide air movement. LED lights were used to extend day length and supplement photons delivered to the plants. The effect of these control measures, in the CEA greenhouse, was evaluated by measuring temperature and humidity variations. Plant growth parameters (plant height, stem diameter, and leaf surface area) were evaluated for the two greenhouses. The mean saturation effectiveness of the coconut fibre cooling pad material used in the evaporative cooler was found to be 25.3%. While, the temperature and relative humidity in the non-controlled greenhouse were higher; those in the CEA greenhouse were lower than the ambient temperature. The CEA greenhouse had significantly higher growth rates in all plant growth parameters (about two and a half times on the average) than the non- controlled greenhouse. The combination of blue LED light, evaporative cooling, and air circulation fans coupled with natural ventilation resulted in a significant increase in plant growth rates in the CEA greenhouse compared to the greenhouse with only natural ventilation as the weather control measure. Keywords: Greenhouse, controlled, environment, Trinidad and Tobago 1. Introduction Trinidad and Tobago's food import bill is currently approximately USS 0.6 billion per annum (Flemming et al., 2015). There is an urgent need to increase food production and reduce this expenditure. Protected agriculture has been proposed as one way to improve agricultural output, by protecting the crops from harsh weather conditions and pests and diseases (DeGannes et al., 2014). If well implemented and followed through intelligently, protected agriculture environment systems will aid in ensuring food security. According to Jensen and Malter (1995), protected agriculture (PA) is "the modification of the natural environment to achieve optimum plant growth." In general, greenhouses are environments which can be controlled to a much higher degree than outdoor fields. Greenhouses involve both passive and active ways of controlling the growing conditions inside the green house. Temperature, light, air humidity, water supply and carbon dioxide in the air can be regulated by the grower. In some modem greenhouses, even infestation by pests and pathogens can be restricted or prevented (EGTOP, 2013). Martin et al. (2008) reported the rejuvenation in the use of greenhouses in Trinidad and Tobago following a collaborative approach by Agricultural Development Bank (ADB) and others to provide financial, marketing and technical support to persons interested in greenhouse crop production. Sahadeo et al. (2017) investigated the existing greenhouses, locally, regionally and internationally and designed and optimised a new system that could potentially be used in the Caribbean region. They found that while most designs could protect the crops from pests and diseases, temperature and humidity could be reduced only marginally by altering their designs, and changing some materials. They, however, found that to control the environmental parameters adequately, Controlled Environment Agriculture (CEA) greenhouses may be needed in the Caribbean. CEA is a subset of protected agriculture in which case all aspects of the natural environment are modified for maximum plant growth and economic return (Jensen and Malter, 1995; Albright and Langhans, 1996). Control may be imposed on air, temperature, light, water, humidity, carbon dioxide, plant nutrients alongside with complete climatic protection (Jenson and Malter, 1995). Tian et al. (2014) did a comprehensive assessment of a controlled growth environment in which they analysed the effect of environmental factors, like temperature, humidity, light, carbon dioxide and nutrients, on crop development. Their results showed that rapes grew very well; the growth period was short with higher quality yields than rapes grown in natural environment. EFTA01223096 M. StaMer at: A Confrolled &yammers; Agriculture Greenluntse for the Caribbean Region I The major disadvantage of the CEA greenhouses is that they are very costly and may not be affordable to most local farmers. Before heavy investments are made, it is, therefore, necessary to construct a prototype CEA greenhouse and compare its performance locally (in terms of controlling temperature, humidity and other environmental factors) to a greenhouse with minimal means of weather control. Such an investigation will reveal whether the CEA greenhouses could lead to better crop yields and control of weather conditions. This paper starts the investigation of CEA greenhouses in Trinidad by first designing and constructing a prototype CEA greenhouse and testing its performance against a similarly constructed naturally ventilated greenhouse. This research will predict the feasibility of large-scale use of CEA greenhouses in Trinidad and Tobago and in the Caribbean. 2. Existing Methods for Modifying the Environment in CEA Greenhouses De Gannes et al. (2014) identified the following problems with CEA greenhouses in the Caribbean: high temperatures, high relative humidity, high carbon dioxide concentration, low oxygen, reduced light especially below minimum threshold level during rainy/cloudy days. Karlsson (2014) reviewed the various methods of controlling environment in greenhouses (see Figure 1). For instance, temperature is controlled by using natural ventilation, exhaust fans, evaporative cooling, mist cooling and shade curtains. Relative humidity is modified by using circulating fans, exhaust fans, natural ventilation and dehumidifiers. Supplemental lighting is provided using incandescent light bulbs, halogen was NAYS Eased teal E•mxtean <Mica Mit Coolies Tea•Grann Viniates a. Ut Rain Heft c.c.s., Mae Mr _ _rase. IR & VneYie ir E Al Moven C•IINSINV HA! Dna Septtenntil Lem.. • Deist ** kr It o 00 • • „MAU, Figure I. Methods of controlling greenhouse environment incandescent bulbs, fluorescent bulbs, high intensity bulbs or light-emitting diodes (LED) lights. In a CEA greenhouse, an integrated computer system is used to ensure that ventilation, humidity, light intensity, carbon dioxide levels and all other parameters operate in harmony with one another so as to provide the best growing conditions (Albright and Langhans, 1996). While simple on-off switches may be used, a computerised system offers remote monitoring and controls based on specific plant requirements (Karlsson, 2014; Goldammer, 2017). Sensors are placed in greenhouses to acquire data. For sensors to be effective, they must be kept at plant canopy height with limited direct influence from vents, fans or drafts (Karlsson, 2014). In computerised systems, sensors send data through a data acquisition (DAQ) device for signal conditioning or through an analogue-to-digital converter (ADC) to computer software to analyse and process this data, to activate some type of control. Information from the computer software is used to activate the actuators using digital-to-analogue convertors. Thermostats or controllers are also utilised in CEA greenhouses. While thermostats control temperature, controllers continuously monitor the greenhouse environment (Karlsson, 2014). Cheap and non-complex on/off systems (Goldammer, 2017) allow sensors to be directly connected to environmental controllers that use relay controls to switch on and off of pumps and fans. This is one way of reducing the cost of CIA greenhouses and was adopted in this study. 3. Design and Construction of Prototype Greenhouses Two prototype greenhouses were constructed and placed alongside each other (see Figure 2). Both greenhouses utilise the Quonset structure which has been altered to improve natural ventilation, by means of a butterfly vent. De Gannes et al. (2014) recommended the Quonset model of greenhouse with a split-roof as the best for the Caribbean region. Sahadeo et al. (2017) modelled and tested this model and verified this recommendation. Greenhouse A is a CEA greenhouse, while Greenhouse B is also a protected agriculture structure but with natural ventilation as the only means for controlling environment. The latter greenhouse was constructed so that both greenhouses could be tested side to side to see if there are advantages of the CEA greenhouse. Each greenhouse is 2 m length, 1.5 m width and 2 m depth. The framework of the greenhouses was constructed with 12.5 mm and 25 mm.diameter polyvinyl chloride (PVC) pipes. PVC cement was used to stick all the pipes into their fittings. The greenhouse frame was covered with a 0.15 mm thick, ultra violet (UV) resistant, low density, clear polyethylene glazing material with a light transmittance of 80% to 90%. The main structure and glazing of protected greenhouses have been fully 11 EFTA01223097 M. Ramjet at: A Conrrolled Environmem Agriculture Greenhouse for the Caribbean Region 12 la) Greathouse A: With contolkd CRY 1/011I Kit described by Sahadeo et al. (2017). Figure 3 shows the diagram of the CEA greenhouse (Greenhouse A). lobs a phij_ (b) GI Celli10.1% B With so conunlled nat011131CIII Figure 2. The two constructed prototype green houses Figure 3. Controlled Environment Agriculture greenhouse (Greenhouse A) Temperature control was achieved using two extractor fans (each 30.5 cm diameter) and a pad evaporative cooling system. The pad frame (1.6 m width, 0.8 m height and 0.762 m thickness) was constructed using pitch pine pieces. The pad material was shredded coconut fibres. Deoraj et al. (2015) found that coconut fibres are efficient for local use as pad material in evaporative coolers. For maximum efficiency and effectiveness, the greenhouse was designed to be air- tight, so that there was no disruption in or alternative path to airflow. Extractor fans drew the air from outside through the pad, since nature does not allow for a vacuum. The pad was continuously being wetted by a 0.01 hp pump (not shown in Figure 3) which supplies water to it from a tank. As the air passed through the wet pad, it was cooled by evaporation. Evaporative cooling, however, works best in less humid conditions, since the cool, moist air being drawn through the pad adds humidity to the environment. The efficiency of evaporative coolers was tested in Trinidad by Deoraj et al. (2015) with some limited success. The CEA greenhouse therefore utilised in addition, natural ventilation so as to ensure that even without any of the automated systems being engaged, air was constantly exchanged between the external and internal environment, so that the crops got a fresh intake of air regularly. As the hot air expands and rises, it escapes the greenhouse through the butterfly vent. When the internal temperature of the greenhouses exceeds maximum threshold of about 35°C (monitored by a temperature controller), the evaporative cooling system will be activated, the exhaust fans and pump will switch on and the evaporative cooling process will start. When the temperature drops to the optimum level, the system will disengage. When the humidity inside the greenhouse exceeds 70% (monitored by a humidity controller), the two circulating fans (each 100 mm diameter), will switch on. When the humidity drops below 70%, the circulating fans will switch off. However, if the exhaust fans of the evaporative cooling system are on, the circulating fans will not switch on and vice versa. This is to avoid turbulence and vortices from developing due to the simultaneous circulation of air and the air being pulled through the greenhouse by the extractor fans. Supplementary lighting was achieved using three light emitting diode (LED) fixtures. LED grow lights (Figure 3) have several advantages over traditional light sources: They are energy efficient, cheap to maintain and are long-lasting (Karlsson, 2014). The LED lights encourage photosynthesis and crop growth (Tian et al., 2014; Suraj, 2017). 4. Testing of the Constructed Prototype Greenhouses Two tests were carried out. The first test examined the efficacy of the coconut fibre as an evaporative pad on two operating parameters of evaporative cooler (saturation efficiency of the evaporative pad and the temperature difference between the ambient conditions and the inside of the CEA greenhouse). The procedure used by Deoraj et al. (2015) was used in this study. A tank was filled with pipe-borne water (Tag = 28.6°C) and the pump was switched on. The airflow rate of the extraction fans was measured with an anemometer. Wet and dry bulb thermometers were used to measure the wet and dry bulb air temperatures entering the evaporative pad and another dry bulb thermometer was used to measure the temperature of the air entering the greenhouse. Temperatures were measured every 15 mins for 3 hours. The test was performed in the morning (9.00 a.m. to 12 noon) and it was repeated in the evening from 1 p.m. to 4 p.m. The saturation effectiveness of the evaporative cooling pad was calculated using the Equation 1 (ASHRAE, 2007). e — x 100 t s— 9 12 EFTA01223098 M. Ramie: at: A Confrolled Environment Agriculture Greenhouse for the Caribbean Region 13 Where E is saturation efficiency (%), ti is dry bulb temperature of entering air (K), t2 is dry bulb temperature of leaving air (K) and t' is the wet bulb temperature of entering air (K). The second test involved the planting of some vegetable crops in both greenhouses to test the efficiency of the CEA greenhouse. Two plant troughs, each 120 cm length and 60 cm width were filled with peat moss mix to a depth of 20 cm, and placed in the two greenhouses (see Figure 2). The troughs had openings at the bottom which allowed for drainage. Seedlings of the same maturity (two weeks old) collected from a nursery were transplanted to the two troughs. The crops in each trough included 3 plants of 535 variety roma tomatoes (Solanum lycopersicum 'Roma'); 3 plants of bronze lettuce (Lactuca saliva Mignonette Bronze); and 3 plants of pak choi (Brassica rapa spp. Chinensis). The troughs were manually watered every day at 9.00 a.m. at the rate of 9 Litres day' for the three weeks of testing. A fungicide (Carbendazim, 50SC) was sprayed onto the leaves of each plant weekly. Plant heights, and stem diameters were measured three times a week with a ruler and Vernier caliper respectively. Leaf areas of each plant were measured using a grid paper. The ambient temperature and humidity as well as those for the greenhouse with natural ventilation were measured with a digital thermo.hygrometer, while those for the CEA greenhouse were recorded by temperature and humidity controllers. Readings of temperature and humidity were taken from 9.00 a.m. to 12 noon, as well as from 1.00 p.m. to 4.00 p.m. every two days. 5. Results and Discussion 5.1 Saturation Effectiveness and Temperature Difference Table I shows the saturation effectiveness of the evaporative cooling pad and the temperature difference between the ambient air and inside of CEA greenhouse (Greenhouse A). The average saturation effectiveness attained for the coconut fibre pad was 25.3% (morning: 19% and 31.5% in the evening). The saturation effectiveness corresponds to temperature difference Table 1. The temperature difference between the ambient air and inside of CEA greenhouse Period of Naming period (940 am. to 12noon Evening period f 1 pm. to 4 pm.) testing Temperature Saturnia, Temperature SatunOtm tains) afftrince M effectiveness(%) ci ff t r 1 f a (a • ff • <9 i t 9 e IS (9) 0 15 MO 3.0 42 30 23 30.7 20 36.4 8) 20 26.7 1.0 22 9) 15 214 13 27.3 120 10 no 25 CO 193 as 9.1 13 27.3 193 05 100 13 210 Saturation effectiveness and temperature difference, as expected, were higher in the evening than in the morning and this agrees with results by Dagtekin et al. (2009) as the weather conditions throughout the day affected the system. These values were much lower than the corresponding average values of 53.5% and 3.6 °C found by Deoraj et al. (2015) for coconut fibres similar to the ones used in this test. They operated their fans at 4 m/s, 6 m/s and 8 m/s compared to average of 2.4 m/s speed of the extraction fan in the present tests. Several other factors which affect pad performance including surface area of the pad, pad thickness, size of perforation of the pads, relative humidity of air passing the pad, volume of water used and number of layers may also have contributed to the lower values obtained (Sreeram, 2014). 5.2 Temperature and Humidity in the Ambient Air and in Greenhouses A and B Figures 4 and 5 show the average daily temperature and humidity of the ambient air as well as those in Greenhouses A and B during the crop growth test period, respectively. —e—Asobtout —e— nub use —•—• Crime/souse 5 10 15 20 Days of testing Figure 4. Temperature of the ambient air and inside the two greenhouses 65 7,, 62 • .59 L• 56 • A IC. 53 —4— Ambtent --a—Cr entlionte A Ci eel thotive a 0 5 10 15 20 Days of testing Figure S. Relative humidity of the ambient air and inside the two greenhouses 13 EFTA01223099 M. Surar et at: A Confrolled Environment Agriculture Greenhouse for the Caribbean Region 14 Results show that the temperature and relative humidity inside the CEA greenhouse (Greenhouse A) were lower than those for the ambient air. This is not surprising since the temperature and relative humidity of the CEA greenhouse were controlled via evaporative cooling and air circulation, respectively. The reverse was obtained for Greenhouse B where the lack of control meant that the two parameters were higher than the values for the ambient air. It was shown in Section 5.1 that the evaporative system was able to effectively reduce the temperature from ambient conditions by 1.6°C. Greenhouse B on the other hand had no accommodation for control of air movement other than natural ventilation, making the humidity higher than that in the CEA greenhouse. 53 Plant Growth Parameters in the Two Greenhouses The plant parameters used to compare the performance of the two greenhouses were plant height, plant diameter and leaf area. Obtaining the three parameters required nondestructive tests. Table 2 shows the values of the plant height and plant diameters of the three vegetable crops. Average growth rates for the height and diameter were calculated by subtracting the initial value of the parameter from the final value and dividing by the test period (19 days). The heights and diameters of all the three crops were much higher in the Greenhouse A (CEA greenhouse) than in Greenhouse B with natural ventilation. On the average, the average growth rates in the Greenhouse A, in terms of height, were at least 1.77, 2.67 and 3.88 of the values in the Greenhouse B for tomatoes, lettuce and pak choi, respectively. For the crops, the respective values for plant diameter were 1.12, 2.4 and 55. This suggests that the CEA greenhouse was most effective for the pak choi and least for tomatoes. Thus, it is evident that a combination of all the control variables (temperature, humidity, light intensity and air movement) was responsible for the improvement in plant growth in the CEA greenhouse. Wheeler et al. (1991) were the first to propose that plant developmental response to blue light (400 — 500 nm) was dependent on absolute blue light for stem elongation in soybean. Blue wave lights affect phototropism, the opening of stomata (which regulates a plant's retention of water) and chlorophyll production (Reece and Campbell, 2011). Crops in CEA greenhouse were grown under LED blue light. Plant stem diameter changes due to both cambial growth (microstructural layer responsible for secondary growth of stems and roots) and water content (Sevanto, 2003). With higher temperature, the plant transpires at a faster rate, causes exhaustion and lack of water retention in the stem of the plant. Figure 6 shows the growth of the leaves in the three crops during the testing period. The results followed the same trend as for plant height and stem diameter discussed above, with the CEA greenhouse having much larger areas for the three crops than Greenhouse B (about two and half times on the average). The best results for the CEA greenhouse were obtained for pak choi followed by lettuce and then tomatoes. The values widened as time of testing increased showing that the differences in plant development between the two greenhouses are expected to increase as the growth period extends. Shin et al. (2001) found that leaf area, stem length and stem diameter generally increased with decreasing temperature. Wang et al. (2014) demonstrated that LED blue light optimised photosynthetic performance by improving the photosynthetic rate, increasing leaf area and prolonging active photosynthesis duration under low irradiance. Chlorophyll absorbs light within the range of 400.500 nm most effectively (red and blue light). Table 2. Growth parameters for the three crops during the test period Days alter planting Tomatoes Lettuce Pak choi Height Stem diameter Height Stem diameter Height Stem diameter (cm) (x 104 cm) (cm) (x 104 cm) (cm) (x I (fi cm) 1 11.0•!11.0 0.154/0.155 7.6/7.0 0.297/0.294 5.7/5.7 0.197/0.196 3 12.4/123 0.161/0.159 8.9/7.1 0.313/0.310 8.6/6.0 0.207/0.199 5 14.9/14.4 0.171/0.165 9.9/7.7 0.321/0.314 9.9/6.9 0.234/0.214 8 20.5/16.9 0.195/0.179 11.218.1 0.331/0.318 11.2/7.6 0.303/0.215 10 23.5/185 0.219/0.193 11.9/8.6 0.335/0.320 13.018.3 0.326/0.223 12 26.6/19.6 0.225/0.213 13.0/9.1 0.346/0.326 14.6/8.9 0.367/0.243 15 29.6/21.6 0.247/0.245 14.0/9.5 0.368/0.338 15.9/10.2 0.387/0.257 17 30.0/21.7 0.257/0.246 14.6/9.7 0.383/0.339 16.1/10.4 0.416/0.264 19 30.2/21.9 0.259/0.248 15.2/9.9 0.405/0.340 16.4/10.5 0.435/0.278 Average growth rate (cm or mm day'/) 1.01/0.57 0.0055/0.0049 0.40/0.15 0.0057/0.0024 0.97/0.25 0.238/0.0043 - Values of the growth parameters are average for the three plants in the Greenhouse A/Greenhouse B. 14 EFTA01223100 M. Sum.) et at: A Con rolled Environmem Agriculture Greenhouse for the Caribbean Region 15 10 IS Days:trier planting 100 90 tr• 80 g 70 E 60 50 t 40 30 a. 20 10 80 70 60 1 50 • • 40 • 30 • 1 g 20 • I0 • 0 0 (a) Tomases 20 (b) 5 tO IS Dstyx a fter planting 20 (C) Pak Mei 5 10 IS 20 Days ark, planting • ,(" et he se A titeenhetaie B Greenhouse A •eGreenhouse B . .13reenbouse A eGreenbouseB Figure 6. Values of mean leaf area for the three types of crops in the two greenhouse during the testing period 6. Conclusion A CEA greenhouse was designed, built and tested by examining the effects of different control parameters on system performance and plant growth. The saturation effectiveness of the pad and temperature difference between the ambient and the inside of the CEA greenhouse were found to be 25.3% and 1.6°C respectively. The impact of controlling temperature and humidity on the CEA greenhouse was assessed, by comparing the results to those of the non.controlled environment and ambient conditions. The results indicated that the controlled environment provided effective cooling and humidity reduction, whereas the non•controlled environment elevated ambient temperature and humidity conditions. Plant growth parameters (height, stem diameter and leaf surface area) within the CEA greenhouse were much greater than those for the naturally ventilated greenhouse. The combination of using blue LED light, evaporative cooling, and air circulation fans coupled with natural ventilation gave a significant improvement in plant growth rates in the CEA greenhouse. The total cost for two greenhouses was about USS 600. Further work will evaluate the efficiency and cost of fully functional CEA greenhouses so as to further validate these findings. Instead of the simple on/off switches method utilised to control the CEA greenhouse environment, an integrated computer control system will be investigated in future research. References: Albright. I-13. and Langhans. R.W. (1996), Controlled Agriculture Scoping Study: Controlled Environment Agriculture Programme. Cornell University. Ithaca. NY 14853. Accessed June 22. 2017 from:httpl/www.comellcea.com/attachments/Controlled%20Env ironment%20Agriculture%20Scoping%20Study%20pdf%20- %20Adobe%20Acrobat%20Professional.pdf ASHRAE (2007). ASHRAE Handbook. Fundamentals. SI Edition. American Society of Heating. Refrigerating and Air-Conditioning Engineers. Atlanta Dagtekin, M., Cengiz K., and Yilmaz Y. (2009), "Performance characteristics of a pad evaporative cooling system in a broiler house in a Mediterranean climate". Biosystems Engineering. Vol.103. No.l. pp.100-104. DeGannes. A., Hem. K.R., Mohammed. A.. Paul. C.. Rowe. J.. Sealy. L. and Seepersail. G. (2014). Tropical Greenhouse Growers Manual for the Caribbean. CARDI. Trinidad. Deoraj. S.. Ekwue. El.. and Birch. R. (2015). "An evaporative cooler for the storage of fresh fruits and vegetables". West Indian Journal of Engineering. Vol.38. No.l. pp.86- 95. EGTOP (2013). Final Report on Greenhouse Production (Protected Cropping). Expert Group for Technical Advice on Organic Production. European Commission. Brussels Accessed. June 27.2017 from: http://edepotwur.n1/414544 Flemming. K.. Minott. A.. Jack. H.. Richards. K. and Opal. M. (2015). "Innovative Community-Based Agriculture: A Strategy far National Food Production and Security". The 2nd Biennial Community Development Partnership Forum and Exhibition. Ministry of Community Development. Port of Spain. Trinidad and Tobago. July. Accessed November 22 at: http://cms2.caricom.oredocuments/B336-innovative community-based-agriculture-strategy-for-national-food-prod- and-security-by-cardi.pdf Goldammer. T. (2017). "Greenhouse Environmental Control Systems" Greenhouse Management: A Guide to Operations and Technology. 1st Edition. (Chapter 4). Apex Publishers. Accessed June 27. 2017 from:http://www.greenhousemanagement.com/greenhouse_mana gement/greenhouse_environmental_control_systemshypes_contr ol_amipment.htm Jenson. M.H. and Maher. AJ. (1995). Protected Agriculture - A Global Review. World Bank Technical Paper No. 253. Washington D.C.. USA. Karlsson. M. (2014), Controlling the Greenhouse Environment. University of Alaska. Fairbanks Cooperative Extension Service. Accessed June 2014. from: httpsi/www.uaf.edullileskes/publications-db/catalog/anr/14GA- 00336.pdf Martin. C.C.G.. Bedasie. S.. Ganpat. W.G.. Orrigio. S.. Isaac. W.A.I., and Brathwaite. R.A.I. (2008). "Greenhouse Technology 15 EFTA01223101 M. Surajer at: A Controlled Environment Agriculture Greenhouse for the Caribbean Region 16 is once again washing the Caribbean. Can we ride the wave this time around? Proceedings of the International Congress on Tropical Agriculture. Hyatt Regency Trinidad. Port of Spain. December pp. 144-152. Reece. J.B and Campbell. N.A. (2011). Biology. 9th Edition. Pearson Education. California. Sahadeo. S.. aWUC. E.I.. and Birch. R.A. (2017). "Survey and modeling of protected agriculture systems in Trinidad and Tobago". West Indian Journal of Engineering. Vol.39. No.2. pp. 46-57. Sevanto. S. (2003). Tree stem diameter measurement and sap flow in Scots pine. Report Series in Physics. University of Helsinki. Finland. Accessed on June 23. 2017 at: http://ethesis.helsinki.fi/julkaisutimatifysildvIchevanto/treestem.p df Shin. H.K.. Lieth, J.H., and Kim. S-H. (2001). "Effects of temperature on leaf area and flower size in rose". EFFE Proceeding III IS Rose Research. Acta Horticulture. 547. ISHS 2001 CTS OF. Accessed on June 21. 2017 from: httpitlieth.ucdavis.edutpubtPub0413_ShinLictliKim.pdf Sreeram. V. (2014). Factors affecting the Performance Characteristics of Wet Cooling Pads for Data Centre Applications. Texas. MSc. Thesis. The University of Texas. Arlington. Accessed June 23. 2017 from: htips://uta- iridtorgiuta- iribitstreanithandle/10106/24977/Sreeram_uta_2502M_I 2973.pd Kosequenc=1 Suraj. M. (2017). Design and Construction of a Miniature Controlled Atmosphere Greenhouse. BSc. Project Report. Mechanical and Manufacturing Engineering Department. The University of the West Indies. St. Augustine. Trinidad. W.I. Tian. L.. Meng. Q.. Wang. L and Does. J. (2014). "A study on crop growth environment control system". International Journal of Control and Automation. Vol.7. No.9. pp.357-374. Wang. L. Czedik-Eysenberg. A. and Mertz R.A. (2014). "Comparative analysis of C4 and C3 photosynthesis in developing leaves of maize and rice". Nature Biotechnology. Vol.32. pp.1158-1165. Wheeler. R.M.. Mackowiak. C.L and Sager. J.C. (1991). "Soybean stem growth under high-pressure sodium with supplemental blue lighting". Agronomy Journal. Vol.83. pp.903-906. Authors' Biographical Notes: Maria Sung holds a BSc. Mechanical Engineering from The University of the West Indies (UWI). with special focus on Energy Engineering. She was one of the founding members of the VIVI Student Chapter of the Institution of Mechanical Engineers (!Mesh£), serving as Class Representative from 2013 to 2014. then as Vice Chairperson from 2014 to 2015. Ms. Suraj is an affiliate member of thlechE and APETE She intends to specialise in Renewable Energy Systems. Edwin I. Ekwue is Professor of the Department of Mechanical and Manufacturing Engineering and Deputy Dean (Research and Postgraduate Student Affairs. Faculty of Engineering. The University of the West Indies. St Augustine. Trinidad and Tobago. He is Vice-Chairman of the Publication Board and former Associate Editor of the West Indian Journal of Engineering. His specialty is in Water Resources. Hydrology. Soil and Water Conservation. Drainage and Irrigation. His subsidiary areas of specialisation are Structures and Environment. Solid and Soil Mechanics. where he has teaching capabilities. Robert A. Birch is an Instructor in the Department of Mechanical and Manufacturing Engineering at The University of the West Indies. St Augustine. T "dad and Tobago. He is a registered Professional Engineer fR.Eng) and Project Management Professional (NIP) with over sixteen years of industrial and teaching experience. He has a BSc. (Eng) and MPhil in Agricultural Engineering from The University of the West Indies and is presently pursuing a PhD in Mechanical Engineering. Mr. Birch is a member of the Institution of Agricultural Engineers (UK). His interests are in Field Machinery and Heat,. Equipment Design. Fluid Power Technology and Soil-Machine interaction. • 16 EFTA01223102