IMPROVING GREENHOUSE HEATING IN PORTUGAL

MICROCLIMATE CONTROL IN GREENHOUSES BASED ON PHYTOMONITORING DATA AND MOLLIER PHASE DIAGRAM

Natural ventilation system facilitates gaseous exchanges in in vitro plants promoting changes in the leaf tissue, which can be evaluated through the leaf anatomy, and it allows a cultivation closer to the photoautrophic micropropagation. The objective of this work was to evaluate the effects on in vitro growth and on the leaf anatomy of Cattleya walkeriana grown in natural and conventional ventilation system with different concentrations of sucrose (0; 15; 30 and 45 L-1) combined with different cultivation systems (conventional micropropagation and natural ventilation system). The culture medium was composed of MS salts, solidified with 7 g L-1 of agar and pH adjusted to 5.8. Forty milliliters of culture medium were distributed in 250 mL flasks, autoclaved at 120 ºC for 20 minutes. The greater plant growth, as well as the greater thickness of the mesophyll was observed with the use of 20 g L-1 sucrose in natural ventilation system. Plants grown in natural ventilation system showed a thicker leaf mesophyll, which is directly related to photoautotrophic crops. The natural ventilation system induced more elliptical stomata and probably more functional formats.

The escalating challenges posed by fossil fuel reliance, climate change, and increasing energy expenses have underscored the critical importance of optimizing energy systems. This paper addresses the economic dispatch (ED) challenge, which directs the optimization of the output of generation units to satisfy electricity and heat requirements while reducing operational expenses. In contrast to conventional economic dispatch methods, this research incorporates renewable energy sources (RESs), energy storage systems (ESSs), and combined heat and power (CHP) systems. This integrated strategy facilitates the concurrent optimization of electrical and thermal generation, culminating in a more comprehensive and efficient solution. A sophisticated scheduling model for combined heat, power, and electrical energy dispatch (CHPEED) has been devised, minimizing generation expenses. The suggested model accounts for practical constraints inherent in real-world power systems, such as prohibited operating regions, while also addressing the intricate relationships between heat and power generation in CHP units. Also, the nature of wind energy, photovoltaic systems, and load requirements within the realm of stochastic dynamic ED are considered. The general algebraic modeling system (GAMS) was utilized to solve the optimization problem. The cost without RES or ESS is $250,954.80, indicating a high reliance on costly energy sources. Integrating RES reduces costs to $247,616.42, highlighting savings through decreased fossil fuel dependency. The combination of RES and ESS achieves the lowest cost of $245,933.24, showcasing improvements in efficiency and supply-demand management via optimized energy utilization. Hence, the findings demonstrate the model's effectiveness in addressing uncertainties associated with renewable generation, ensuring reliability in meeting energy demands and validating the possible capability to enhance the sustainability and efficiency of energy systems.

The potential effects of window configuration and interior layout on natural ventilation buildings: A comprehensive review

The global cooling market is growing at a high rate. There are many factors driving the demand for cooling. Global trends lead to urbanization of cities, rising temperatures, thereby constantly increasing the demand for air conditioning (AC). The largest growth is projected in rapidly developing countries with hot climates such as India, Indonesia, China, etc. The constant increase in environmental and comfort requirements lead to constant improvement of air conditioning technologies and equipment. The level of technology and their average prices change very quickly. Therefore, we must stay informed and be able to choose the most effective technologies for our region and country. The air conditioner market is growing slightly in russia. A large increase in market volume is not predicted in the near future. According to the Goskomstat data, a typical cold consumer is an operating apartment building with central heating and natural ventilation. Therefore, options for ensuring a comfortable climate by modernizing an existing heating system with centralized heating through radiators and natural ventilation systems in buildings should be investigated. This article discusses the possibility of introducing an integrated heat and cold supply system (district cooling) using absorption chillers. Waste heat from combined heat and power plants (CHP) is used as an energy source. The main factors of the economic success of the district cooling (DC) project are analyzed.

This study analyses the use of solar energy in the heating systems of residential buildings and various sectors of the economy, based on scientific research conducted both in foreign countries and in Uzbekistan. The data show that there is significant potential for efficient utilization of solar energy in the southern regions of the country, considering the available solar resources and climatic conditions. However, there are challenges related to the integration of solar-based heating systems into combined configurations. Studies have focused on the effectiveness of using solar eneray throuah the integration of solar collectors, photovoltaic panels, and heat pumps as well as on reducing energy consumption and optimizing production processes. Special attention is given to methods and directions for the efficient use of solar energy that are suitable for Uzbekistan's specific climatic conditions.

Epileptic power supply is a major problem in Nigeria and one of the ways Nigerians have solving this challenge is by using renewable energy as an alternative power supply in place fossil fuels. Among renewable energy sources, solar is the most important because it is available in this part of the world. This energy source is also used in various industries including agriculture and it can be used in irrigation and sprinklers in farmer’s vegetable farm. This research was carried out through field visitations and extensive literature on the performance of photovoltaic modules. This paper outlines the use of solar water pump for irrigation in vegetable farms, the benefits and concludes with suggested recommendations which can help production of vegetables during dry season in Anambra State. It aims at contributing a better understanding of the potential impact of solar photovoltaic (PV) on sustainable production of vegetables with special attention to the effect of income generating activities in the State. It is known that during dry season, vegetables do not get enough water, sometimes these agricultural products are very scarce and expensive. Solar photovoltaic water pumping is found to be economically viable in comparison to electricity or diesel based systems for irrigation and sprinklers in the vegetable farm. Solar photovoltaic water pumping is therefore, an attractive alternative for irrigation and sprinklers in Nigerian vegetable farm due to the huge solar potential in the country.

As climate control in greenhouses directly affects crop yields, there is an increasing trend for advancements in environmentally controlled agricultural-production techniques. In the Mediterranean region, the temperatures during the period from December to February are below 12°C when the daily total radiation 8.4 MJ/m2day. Based on the region?s climate data, greenhouses require heating during the period from November to March, ventilation and shading from February to May and cooling from June to September. In order to maintain day and night temperatures of 18/16°C, annual heat energy requirement of PE greenhouses is 95-256 kWh/m2. In view of environment and production costs, conservation of heating energy is as important as heating itself. Heat energy saving is about 37% when energy curtains are used. Greenhouse temperature can be increased by 8°C in palliative non-heated greenhouses where energy curtains and water mattresses are used in addition to passively used solar energy. Ventilation openings at the roofs of these greenhouses should adequately be 20-25%. When outside noon-time temperature is above 30°C in June, evaporative cooling of greenhouse is essential. Depending on outside humidity and volume of exchanged air for cooling, a temperature difference of 6°C can be achieved with evaporative cooling of greenhouses in August.

Thermal and humidity control in high-geothermal tunnel by natural ventilation during operational transition period: A case study

Nonlinear MPC based on a Volterra series model for greenhouse temperature control using natural ventilation

Integrated Energy Systems (IES) combine on-site power or distributed generation technologies with thermally activated technologies to provide cooling, heating, humidity control, energy storage and/or other process functions using thermal energy normally wasted in the production of electricity/power. IES produce electricity and byproduct thermal energy onsite, with the potential of converting 80 percent or more of the fuel into useable energy. IES have the potential to offer the nation the benefits of unprecedented energy efficiency gains, consumer choice and energy security. It may also dramatically reduce industrial and commercial building sector carbon and air pollutant emissions and increase source energy efficiency. Applications of distributed energy and Combined heat and power (CHP) in ''Commercial and Institutional Buildings'' have, however, been historically limited due to insufficient use of byproduct thermal energy, particularly during summer months when heating is at a minimum. In recent years, custom engineered systems have evolved incorporating potentially high-value services from Thermally Activated Technologies (TAT) like cooling and humidity control. Such TAT equipment can be integrated into a CHP system to utilize the byproduct heat output effectively to provide absorption cooling or desiccant humidity control for the building during these summer months. IES can therefore expand the potential thermal energy services and thereby extend the conventional CHP market into building sector applications that could not be economically served by CHP alone. Now more than ever, these combined cooling, heating and humidity control systems (IES) can potentially decrease carbon and air pollutant emissions, while improving source energy efficiency in the buildings sector. Even with these improvements over conventional CHP systems, IES face significant technological and economic hurdles. Of crucial importance to the success of IES is the ability to treat the heating, ventilation, air conditioning, water heating, lighting, and power systems loads as parts of an integrated system, serving the majority of these loads either directly or indirectly from the CHP output. The CHP Technology Roadmaps (Buildings and Industry) have focused research and development on a comprehensive integration approach: component integration, equipment integration, packaged and modular system development, system integration with the grid, and system integration with building and process loads. This marked change in technology research and development has led to the creation of a new acronym to better reflect the nature of development in this important area of energy efficiency: Integrated Energy Systems (IES). Throughout this report, the terms ''CHP'' and ''IES'' will sometimes be used interchangeably, with CHP generally reserved for the electricity and heat generating technology subsystem portion of an IES. The focus of this study is to examine the potential for IES in buildings when the system perspective is taken, and the IES is employed as a dynamic system, not just as conventional CHP. This effort is designed to determine market potential by analyzing IES performance on an hour-by-hour basis, examining the full range of building types, their loads and timing, and assessing how these loads can be technically and economically met by IES.

Indicators at a global level are presented: population in the world today and forecasts for developed and developing countries. The following diagrams are presented: world total primary energy consumption, global CO2 emissions from combustion since 1971, as well as cumulative CO2 emissions by regions since 1750. Facts for climate change are included (according to WMO and IPCC): increase in GHG concentrations, increase in air temperature, rise in sea level, etc. The consequences of global warming are listed: extreme rainfall and floods; high temperatures – heat waves, droughts, wildfires; huge damage to agriculture; harmful impacts on the environment, etc. The IPCC provides several scenarios for a global rise of air temperature up to 2100, for a global rise of sea level etc. The activities of the international community on climate change are organized through: IPCC, UNFCCC, Kyoto Protocol, Paris Agreement and continuous negotiations. The European Union (EU) is probably the most advanced in the battle against climate change. Some important strategies are outlined: by 2020, by 2030, and by 2050. Heating, air-conditioning and refrigeration systems (HVACR) are connected with energy consumption, which means they are a source of GHG emissions. The situation with HVACR systems is such that even in EU countries, the fossil fuels are dominant in the heating systems. Future solutions for HVACR systems are described. The first step is to increase the energy efficiency of buildings and HVACR equipment. The concept of "nearly zero-energy buildings" should be worked on. HVACR systems should be based on renewable energy sources (RES). The considered solutions include heat pumps, solar panels, thermal storage, district heating, combined heat and power, condensing boilers, reversible air conditioners, the concept of "smart" buildings, automation of HVACR systems with digital technology, etc. The political, economic and social aspects of climate change are analyzed. Capitalism society, market economy, profit, is the main reason for today's climate change situation. On the end, there is a discussion highlighting the need for urgent and major investment in RES and energy efficiency. For rich countries, this is really achievable. But developing countries, representing 83% of the world's population, need financial assistance, and this needs to be regulated through the Paris Agreement. Obstacles of a political nature are also possible (US and Paris Agreement).

Promotion of an Efficient Energy Use and Use of Renewable Sources of Energy

Pinch Analysis and Process Integration: a User Guide on Process Integration for the Efficient Use of Energy

This study primarily aims to investigate the improvement in indoor thermal conditions by passive cooling approaches without auxiliary cooling from air-conditioning equipment. A field study is carried out in The View apartments, Penang, Malaysia, to ascertain the environmental performance of these glazed residential buildings. This study explores the potential of using natural ventilation as a passive cooling system for residential buildings in Malaysia. The impact of natural ventilation strategy is investigated in selecting different rooms, days and orientations. The impact of daytime and nighttime natural ventilation as a passive cooling strategy is also investigated and compared with that of unventilated situations. Results show significant improvements in indoor environmental performance by 80% and 50% at daytime and night-time, respectively, in cases where natural ventilation is applied and considered in the building. Keywords: Hot–Humid Climate, Natural Ventilation, Residential Building, Sustainable Design, Thermal Performance