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Heat requirements in greenhouses are calculated considering greenhouse type, the climate of the region and temperatures desirable for plant growth. Calculations made according to daily average temperature values lead to misleading results during periods when temperatures are high and under conditions when greenhouse temperature is kept low. For this reason, determining heat requirements according to hourly values provides more accurate results. Calculations of heat requirements in greenhouses are based on the difference between the desired temperature in the greenhouse and the outside temperature. However, in unheated greenhouses and those that are not ventilated until a specific temperature, actual temperature values are higher than outside temperatures. For this reason, heat requirement calculations should be made according to hourly climate values taking into account actual temperature in the greenhouse and temperature rise resulting from greenhouse specifications. This study aims to compare the amounts of fuel consumed under real conditions with fuel consumption calculated with conventional methods using inside and outside temperature difference and considering the above mentioned inconveniences. Daily fuel consumption calculated theoretically differs from actual consumption values. However, in comparisons based on fuel amounts consumed on an annual basis, best results were obtained when temperature rise in the greenhouse was taken into consideration. In the event that temperature rise is taken into consideration, a 3% difference is observed between calculated fuel consumption and actual fuel consumption.

Wireless sensor networks applications and inter-machine communication (M2M), called the Internet of Things, help decision-makers to control complex systems thanks to the low data-rate and cost-effective data collection and analysis. These technologies offer new possibilities to monitor environmental management and agricultural policies, and to improve agricultural production, especially in low-income rural areas. In this study, IoT is proposed with a low cost, flexible and scalable data collection and analysis system. For this purpose, open source hardware microprocessor cards and sensors are stored in the greenhouse computer database using the IEEE 802.15.4 Zigbee wireless communication protocol. The data can be analyzed by greenhouse computer analysis software, which is developed with the PHP programming language. It is possible to monitor the real time data from the greenhouse computer. Also alert rules definitions can be made and the system was tested in greenhouse conditions. It has been observed that it performs operations steadily such as data transfer, sensor measurements and data processing. The proposed system may be useful for monitoring indoor climate and controlling ventilation, irrigation and heating systems, especially for small enterprises due to the modular structure.

Ventilation is one of the methods used to obtain the biological optimal point of environmental factors needed for the plants in greenhouses. In the greenhouses, air change coefficient must be more than 50 h-1 in order to supply effective air ventilation. Temperature differences like air change coefficient can be regarded as a criterion to determine efficiency of ventilation in the greenhouses. In this study, the temperature values were calculated by using energy balance and Bernoulli equation at different ventilation opening ratios (AV/AG) depending on climatic properties in the Mediterranean region (Antalya). If was found that, based on temperature and radiation values of Antalya province, 20% ventilation opening rate is sufficient in the roof area. A temperature difference (∆T) of 1K can be achieved with a 50% shading of radiation and a 20% ventilation opening in June in the Mediterranean region. However, additional cooling is necessary in the greenhouses around noon hours because outdoor temperature is greater than 30°C.

In Mediterranean climate region, during certain times of the year the daily average temperature decreases under 12°C. In such conditions, greenhouse heating is essential to be able to get the high quality yield that is expected from greenhouses. The cost of heating varies from 20% to 60% of the total costs depending on the climate of the region, size, type and hardware of the greenhouse and type of plant grown in the greenhouse. The heat requirement in greenhouses is calculated based on the rudiments defined by DIN 4701 standards. However, the real temperature in greenhouses is higher than the outside temperatures used in calculations. For this reason, the heat requirement in greenhouses should be calculated by taking temperature increases that are caused by ventilation temperature and heat storage capability into consideration. In this study, the heat energy need of Antalya which is located in Mediterranean region is assessed according to its climate conditions. In the calculations, the different hardware structures are considered and the level of energy that can be saved is calculated. As a result of the calculations, depending on the month of the year, 12% to 29% difference is observed between energy requirement calculations based on the indoor temperature increases and energy requirement calculations based on outside temperature values.

Vaporpressuredeficitandthehightemperatureemergedduringthesummer months in thecountrieswithMediterraneanclimate, resultsin decrease of thequantityandthequality of theproductsproduced in greenhouses. Duringthisperiod, toreducetheplantstressand in ordertoprovidehighqualityproductstothe market, greenhousesarerequiredto be cooled. Inordertoreducethetemperatures in greenhouse, naturalventilation is thefirstmethodconsidered. Althoughnaturalventilation; is cheaperthantheotherforced methods in terms of thefirstinvestmentandoperatingexpenses,it is not enough to reduce the high temperatures in the greenhouse during the periods when the temperatures are starting to increase.The advantage of the forced ventilation methodwith fansis the higher amount of air exchange ratio and the ability to control ratio compared to natural ventilation.This method, too, is insufficient in the summer months to reduce the high temperatures inside the greenhouse.Anothermethod is theshadingmethod; whichhelpsto lowerhightemperatures in theinside thegreenhousebyreducingtheradiationreachingthegreenhouse. Inthismethod, reduced temperaturelevelinside thegreenhouse is insufficientforplantgrowth, andalsoimproperuse of thismethodcausesreduced use of sunlightby plants.One of the most effective solutions for cooling the greenhouse during these periods when natural ventilation, forced ventilation and shading methods are inadequate is evaporative cooling.Inthisstudy, ventilation(natural and forced), shading and evaporative cooling methods, used toreducethe effect of high temperature that occursin greenhouses, and advantages and disadvantages of these methods have been evaluated.

The most extensive and effective environmentally controlled production takes place in greenhouses. New innovations and developments for greenhouse production go hand in hand with efforts for sustainability. The greenhouses must be heated to ensure high yields and high quality. However, high heating cost (20%-60%) adversely influences production. Costs Sustainability of greenhouse production can only be maintained with increase of energy efficiency. Use of renewable energy sources in place of fossil fuels is only means to increase energy efficiency. In this work, fossil fuels and geothermal energy used for heating of greenhouses are compared based on production cost and CO2 emissions to atmosphere. The results showed that greenhouse production in Aydın with geothermal energy price of 0.06 ₺/kWh will be very advantageous compared to greenhouse tomato production in Kütahya, which can only compete with that in Antalya. Carbon dioxide emission in plastic greenhouses with double layer PE plastic heat insulation in Kütahya was 199.4 kg/m2 when imported coal was used for heating. The emissions in similar type plastic greenhouses, again heated with coal, in Aydın and Antalya were 74.4 kg/m2 and 55.5 kg/m2, respectively. Greenhouses in geothermal energy rich areas will be very advantageous, based on cost of production and CO2 emission, compared to that in Antalya region if they are heated with geothermal energy.