Genetic Algorithm Based Temperature-Queuing Method for Aggregated IAC Load Control

In recent years, demand response (DR) has played an increasingly important role in maintaining the safety, stability and economic operation of power grid. Due to the continuous running state and extremely fast speed of response, the aggregated inverter air conditioning (IAC) load is considered as the latest and most ideal object for DR. However, it is easy to cause load rebound when the aggregated IAC load participates in DR. Existing methods for controlling air conditioners to participate in DR cannot meet the following three requirements at the same time: basic DR target, load rebound suppression, and users’ comfort. Therefore, this paper has proposed a genetic algorithm based temperature-queuing control method for aggregated IAC load control, which could suppress load rebound under the premise of ensuring the DR target and take users’ comfort into account. Firstly, the model of the aggregated IAC load is established by the Monte Carlo method. Then the start and end time of DR are selected as the main solution variables. A genetic algorithm is used as the solving tool. The simulation results show that the proposed strategy shows better performance in suppressing load rebound. In the specific application scenario of adjusting the frequency fluctuation of the microgrid, the results of the case show that this strategy can effectively control the frequency fluctuation of the microgrid. The effectiveness of the strategy is verified.

Radiant Conditioning Retrofitting for Residential Buildings

In order to achieve Australia’s greenhouse gas emissions reduction targets, a majority of the existing residential building stock in Australia will require retrofitting in favour of energy-efficient solutions. This paper considers retrofitting for conditioning to be one of the most straightforward and offers the greatest potential to deliver significant comfort and energy-saving results. Radiant conditioning systems are not new, yet some game-changing innovations have taken place over the last decade that may require an entire paradigm shift in the manner we condition our buildings. The reiteration of the principle ‘thermally active systems’ suggests that our buildings need to accommodate these systems into the fabric of building components. However, extremely few products and/or innovative solutions for doing such seem to be provided by the industry. We seem incompetent with solutions that are not costing the Earth, insulating, lightweight, and offering an instant response time to conditioning. We still have the concept embedded in our minds that radiative systems consist of heavy ‘combat’ construction with time lags of a day or two and that they are very costly to implement, especially if we are to retrofit a project. The purpose of this paper is to rectify and change our understanding of radiant systems, namely through a review of the existing technology and its recent advancements. It intends to introduce the fact that radiant systems can become highly reactive, responsive, and thermally dynamic conditioning systems. Lightweight radiant systems can be 40% more energy-efficient than common air conditioners and can respond in less than 15 min rather than in the hours required of heavy radiant systems. Thus, an insulated, lightweight radiant system is ideal for retrofitting residential buildings. Furthermore, this paper supports and introduces various systems suited to retrofitting a residential building with hydronic radiant systems.

Rancang Bangun Sistem Monitoring Ruang Kelas Berbasis Internet of Things pada Universitas Pamulang

In a classroom, ideally there are facilities such as chairs, desks, blackboards, and electronic devices used such as air conditioners (AC), lamps and projectors. However, in its use, there are actions that are not responsible for maintaining the facility so that it causes losses. An internet of things-based classroom monitoring system is needed to solve existing problems. This system has the ability to remotely operate electronic facilities in classrooms such as air conditioning, electricity and lights, monitor access to classrooms, process data, print activity monitoring reports, to monitor the current conditions of a room. This system consists of three parts, namely the database part, the microcontroller section and the software section. The database section contains data on access cards or fingerprints, room usage schedules, room temperature and humidity. The methodology for designing and building a classroom monitoring system uses the waterfall methodology. In this methodology, several steps are taken to build a system, namely: system requirements analysis, hardware design and software engineering, system design, system implementation, system testing, and system maintenance. Based on the test results, this system can record input data on the microcontroller section and display it in the software section for real-time monitoring and controlling of classrooms and minimizing damage to existing facilities in the classroom. Monitoring of classroom use that is not according to the schedule of use can be carried out and controlled remotely in real-time.

The Survey of Fungal Contamination in the Air Flowing Out of Air Conditioners (Coolers) in a Car

Background: Fungi are among the most important microorganisms in the air. The air conditioner (cooler) in a car can be an important reservoir for infectious agents, especially fungal species. The present study aimed to measure the fungal contamination in the air flowing out of air conditioners. Objective: In this study 138 cars including 69 Iranian-made cars and 69 cars made by foreign companies were examined. Methods: The plating technique was used. In this study, in each car, 2 plates were placed for 5 minutes when the air conditioner was on and also 2 plates were placed for 5 minutes when the air conditioner was off. Results: A total of 2442 colonies were isolated. The most common isolated fungi were Cladosporium spp. (25.55%), Penicillium spp. (6.14%) and Aspergillus niger (3.03%). The highest number of isolated fungal elements was observed in the Iranian-made cars during summer season (P-value<0.05). Furthermore, the growth rate of colonies on the plates placed on the front and rear seats of cars did not vary considerably (P-value > 0.05). Conclusion: Air conditioners of Iranian-made cars can be an important source for fungal transmission to the human respiratory system that is important, especially in susceptible people to allergic diseases and patients with immunodeficiency.

A Review of Data-Driven Short-Term Voltage Stability Assessment of Power Systems: Concept, Principle, and Challenges

With the rapid growth of power market reform and power demand, the power transmission capacity of a power grid is approaching its limit and the secure and stable operation of power systems becomes increasingly important. In particular, in modern power grids, the proportion of dynamic loads with fast recovery characteristics such as air conditioners, refrigerators, and industrial motors is increasing. As well as there is an increasing proportion of different forms of renewable energy in power systems. Therefore, the short-term voltage stability (STVS) of power systems cannot be ignored. This article comprehensively sorts out the STVS problems of power systems from the perspective of data-driven methods and discusses existing challenges.

RESEARCHES ON THE TESTING IN LABORATORY CONDITIONS OF AN ECOLOGICAL CLIMATE SYSTEM USED FOR SELFPROPELED AGRICULTURAL MACHINES

Nowadays, cooling the air by means of climate maintenance systems is achieved, in most cases, using installations based on freon or other substances that cause pollution. Taking into account the fact that the EEC standards and regulations increase the emphasis on ensuring the quality, labour safety, health and environment, finding a solution for air conditioners that do not use a substance that causes pollution, has become a necessity. As a great part of farming work is done in the warmest periods of the year, temperatures being frequently over 35oC, it is necessary to equip the agricultural machines with air conditioners in order to achieve a thermic comfort in the cab. For this purpose, an air conditioner based on the process of water evaporation was designed, made and tested. The installation is able to cool the air that enters into the cab through the evaporation process that takes place in the special filling, with an efficiency of the mixing process more than 90%. Air passing sections are calculated so that they can assure both the quantity needed for climate maintenance in the cab (about 3.5 - 4 m3/min) and the relative speed between air and water in the filling, in order for the evaporation process to be conducted in the best conditions that were theoretical established.

SYSTEMATIC REVIEW OF SUSTAINABLE DESIGN APPROACH FOR MOSQUE

As one of the prominent public spaces for the community, Mosque is considered one of the high energy consumption buildings. Many modern mosques are designed and built without respecting the contextual environment, resulting in a non-environmental friendly Mosque. In Malaysia, the operating cost of mosques is majorly relying on public funds, and statistically are high specifically for electricity usage. Due to the use of air conditioners in cooling down the huge prayer hall due to the non-environmental design consideration. Hence, it is crucial to justify sustainable design approaches in mosques to develop environmentally friendly mosques. On the other side, the environmentally friendly mosque design is important as one of the monumental Islamic symbols that shall manifest Islam's values and philosophies towards the benefits of 'Alam' (world). The main objective of this study is to analyze the principles of Islamic methods in attaining the attributes of sustainable mosque design. It systematically reviews the existing publications to discover the concepts, definitions, and issues regarding the sustainable design approach-es for Mosque. Based on the conducted reviews, sustainable design strategies for mosques are suggested at the end of this paper. The Mosque can use some renewable technologies to save energy and be concerned about the climate condition for its design. Furthermore, it can also use sustainable materials, use natural ventilation and daylighting to provide good indoor air quality and be concerned about the social life of Muslim's religious activities.

DEVELOPMENT OF ADAPTIVE VENTILATION IN MULTIFUNCTIONAL LARGE-SCALE SPACE OF PUBLIC BUILDINGS

Проанализирована актуальность строительства объектов культурно-массового назначения. Описана целесообразность проектирования многофункциональных трансформируемых помещений для общественных зданий. Приведены достоинства и недостатки применения рециркуляции воздуха как способа энергосбережения. Акцентировано внимание на поддержании чистоты воздуха в помещении и способах борьбы с бактериями и вирусами в приточном воздухе. Предложена схема многозональной общеобменной вентиляции воздуха без рециркуляции с блокированием кондиционеров для взаимозаменяемости с целью обеспечения микроклимата в многофункциональных помещениях общественных зданий. Описана последовательность работы системы вентиляции в теплый и холодный период года. Разработана система рекуперации с промежуточным холодоносителем для теплого периода года. Приведено описание работы установки кондиционирования воздуха. На примере реально существующего объекта выполнено численное исследование режимов работы системы вентиляции с рекуперацией теплоты и холода для трансформируемого помещения. Построен график для определения граничных условий работы рекуператора исходя из соотношения между интенсивностью теплообмена за счёт конвекции и интенсивностью теплообмена за счёт теплопроводности. При различных наружных температурах воздуха и расчетных температурах уходящего воздуха построены графики определения оптимальных параметров температуры воздуха на входе в утилизатор при оптимальных значениях водяного эквивалента . Выявлены и описаны режимы работы кондиционеров с теплоутилизатором в теплый период года, работающих в составе многозональной общеобменной вентиляции воздуха с блокированием кондиционеров для взаимозаменяемости. В ходе численного исследования выявлено, что наибольшая энергоэффективность системы вентиляции с рекуператором будет достигнута при принятии в качестве оптимального значения водяного эквивалента W = 3. We analyzed the relevance of cultural facilities construction. As well, we described the expediency of designing multifunctional transformable spaces for public buildings. Moreover we presented advantages and disadvantages of using air recirculation as a method of energy saving. A special attention is focused on maintaining indoor air clean and on various ways of combatting bacteria and viruses in the intake air. We offered a scheme of multi-zone forced air ventilation without recirculation with blocking air conditioners for interchangeability in order to provide a microclimate in multifunctional spaces of public buildings. We described the sequence of operations in the ventilation system in warm and cold seasons. We also developed a recuperation system with an intermediate refrigerant for warm seasons. The article presents a detailed description of the air conditioning unit operation. We carried out a numerical study of the operating modes of the ventilation system with heat and cold recovery for transformable spaces on the example of a real-existing facility. We show a graph to determine the boundary conditions of the recuperator operation based on the ratio between the intensity of heat transfer due to convection and the intensity of heat transfer due to thermal conductivity. At various outside air temperatures and design temperatures of the outgoing air, we created some graphs for determining the optimal parameters of the air temperature at the inlet to the heat exchanger at the optimal values of the water equivalent. We identified and described several modes of operation of air conditioners with a heat exchanger in warm seasons, operating as part of a multi-zone forced air ventilation with blocking air conditioners for interchangeability. In the course of a numerical study, it was revealed that the highest energy efficiency of a ventilation system with a recuperator could be achieved when the water equivalent value W = 3 is taken as the optimal value.

Potential reduction in drinking water consumption at the headquarters of the Regional Electoral Court of Pernambuco - TRE/PE

Water conservation in buildings includes not only reducing the demand for potable water, but also adopting alternative sources for activities with less noble purposes. Public buildings under the jurisdiction of the Federal, State, and Municipal governments are required to promote actions aimed at the rational use and conservation of water, according to the responsibility established in the Environmental Agenda in Public Administration.In light of the above, this study aims to analyze the potential for reducing drinking water consumption at the headquarters building of the Electoral Regional Court of Pernambuco - TRE/PE through the use of alternative water sources, such as rainwater and condensed water from air conditioners. The methodology began with the characterization of the study site and the consumption of potable water.Subsequently, the technical and economic feasibility of rainwater and condensate water use was investigated, as well as a comparison between the proposed measures. The results obtained indicate that the techniques studied are beneficial, presenting significant potential for reducing the consumption of potable water that would be used for toilet flushing, 63% for rainwater use and 62% for condensate water.In addition, they can also provide annual financial savings of R$8,216.01 and R$8,045.74, respectively. Thus, besides reducing drinking water consumption, the proposed measures also promote the minimization of financial costs, whose capital can be used in the search for continuous improvement of services provided to society.

Energy Efficiency Ratio Analysis of Half Cycle Air-Conditioners Using Liquified Petroleum Gas

Alternative fuels have proven to be an effective means of reducing the environmental impact of road transportation. On the other hand, the increasing use of air conditioning has declined the fuel economy of passenger vehicles. Half-cycle air conditioning systems (HCACSs) can address this concern of the declining fuel economy by using the fuel as a refrigerant. One of the candidates to be considered as refrigerants in HCACSs is liquefied petroleum gas (LPG). Under various conditions, LPG in the liquid state is injected into the evaporator of an HCACS. At the end of the evaporation process, LPG vapors can be directed for the combustion taking place in devices such as generators, automobiles, and cooking stoves. The present study investigates the performance of three in-housed manufactured evaporators having staggered and/or aligned tube arrangements with variable tube sizes, numbers of fins, fin spacings, and fin materials. As a refrigerant, LPG, having 65% propane and 35% butane, was passed through three evaporators. The energy efficiency ratios (EERs) were indirectly measured for evaporative pressures of 132, 168, and 201 kPa, with mass flow rates of 0.6, 0.75, and 0.9 g/s, respectively, when the fan speed interacting with the evaporators was varied. The results revealed that the aligned configuration with the same tube and fin material performed better even at low fan speeds.