the nine patterns is the odd one out and solve as many problems as possible in 90 seconds. The outcome measure is the total correct. The Grammatical Reasoning task requires participants to indicate whether a statement correctly describes a pair of objects displayed in the centre of the screen. In order to achieve maximum points, the participant must solve as many problems as possible within 90 seconds and the outcome measure is the total score. In planning skill, the Spatial Search is based on a test that is widely used to measure strategy during search behaviour (Collins et al., 1998). Some boxes are displayed on the screen in random locations within an invisible 5 × 5 grid. The participant must find a hidden “token” by clicking on the boxes one at a time to reveal their contents. On any given trial, the token will not appear within the same box twice. After 3 errors the test ends and the outcome measure is the maximum level achieved. The Hampshire tree task is an adaptation of the Tower of London/ Tower of Hanoi test (Shallice, 1982; Simon, 1975), which is a widely used clinical neuropsychological tool for assessing planning abilities. Numbered beads are positioned on a tree shaped frame. The participant repositions the beads so that they are configured in ascending numerical order running from left to right and top to bottom of the tree. Participants must solve as many problems as possible in as few moves as possible within 3 minutes and the outcome measure is the total score. Complete descriptions of the 8 cognitiveperformance tests can be found in the Supplemental Information from Hampshire et.al. (2012).
Abstract: A new model predictive control (MPC) algorithm is used to select optimal airconditioning setpoints for a commercial office building, considering variable electricity prices, weather and occupancy. This algorithm, Cost-Comfort Particle Swarm Optimization (CCPSO), is the first to combine a realistic, smooth representation of occupants’ willingness to pay for thermalcomfort with a bottom-up, nonlinear model of the building and airconditioning system under control. We find that using a quadratic preference function for temperature can yield solutions that are both more comfortable and lower-cost than previous work that used a “brick wall” preference function with no preference for further cooling within an allowed temperature band and infinite aversion to going outside the allowed band. Using historical pricing data for a summer month in Chicago, CCPSO provided a 1% reduction in costs vs. a similar “brick-wall” MPC approach with the same comfort and 6–11% reduction in costs vs. other control strategies in the literature. CCPSO can also be used to operate the building with much greater comfort and costs or much lower costs and comfort than the “brick-wall” approach, depending on user preferences. CCPSO also reduced peak-hours demand by 3% vs. the “brick-wall” strategy and 4–14% vs. other strategies. At the same time, the CCPSO strategy increased off-peak energy consumption by 15% or more vs. other control methods. This may be valuable for power systems integrating large amounts of renewable power, which can otherwise become uneconomic due to saturation of demand during off-peak hours. Keywords: heating ventilation and airconditioning (HVAC); model predictive control (MPC); demand response; EnergyPlus; particle swarm optimization (PSO); renewable energy; smart grids MSC: 49M37; 65K05; 90-04; 90B35; 90B50; 90C29; 90C56; 90C90; 91B08; 91B10; 91B26; 91B42; 91B74
As a part of operational strategies, demand side management can be used to reduce residential neighbourhood peakdemand (Pezeshki, Wolfs, & Ledwich, 2014), improve electricity network relia- bility (Narimani, Nourbakhsh, Ledwich, & Walker, 2015) and increase household photovoltaic ener- gy local consumption (Liu, Ledwich, & Miller, 2015). When operational strategies are adopted, building thermal mass performs better to reduce peakdemand. Where summer peak demands are larger than winter’s, pre-cooling using building thermal mass can effectively shave electricity peakdemand, maintain comfort levels as well as avoid creating a new peak in a later time (Katipamula & Lu, 2006; Liu, Ledwich, & Miller, 2016; Perez, Baldea, & Edgar, 2016; Xue et al., 2014). Pre-cooling can also potentially reduce the risk of high charges when the electricity price is volatile (Marwan, Ledwich, & Ghosh, 2012). These studies have opened a gate for cross-disciplinary research be- tween mechanical and electrical disciplines; however existing studies often did not consider the real world demand tariff in smaller time intervals of half hour or less and missed the justification for their proposals’ implementation cost.
Many steps in fluent part are used in (CFD) program . At the begging simulation Problem setup and included Model as shown in Fig-6.Also,The solution to a flow field problems (temperature, pressure, velocity, etc) is defined at nodes for each cell.The number of elements for three cases were 701528, 694643 and 315525 respectivelyas shown in Fig(6). Materials setup which included material properties used in simulation such as density (ρ), specific Heat (Cp)and thermal Conductivity (k)with values1.225, 1005 and0.0454 respectively. The Boundary conditions which has a significant impact on CFD simulation success in giving a reliable results for solved problem. Boundary conditions that imposed in CFD simulation implemented in this work consist of three types:, velocity inlet and outflow as tabulated in table 9. wall boundary included Walls with constant temperatures and also constant heat fluxes from other internal source such as Person, Computer and Light are45, 74.38 and 1000 respectively.
Abstract: The energy consumption of the constant air volume (CAV) system largely depends on the regulation strategies. Although some airconditioning systems are equipped with automatic regulation devices, others lack effective regulation strategies. To avoid wasting energy and presenting simple regulation methods, fuzzy regulation strategies for CAV systems are studied in this research. A CAV system of an office building is modeled and simulated with the Designer’s Simulation Toolkit (DeST). The operating parameters are calculated based on the instantaneous load obtained from simulation. The operation of the system is divided into five stages according to different conception of “cold” or “hot” in different seasons. The relationship between the outdoor air temperature and the fresh air volume, and the supply air temperature is presented in the form of fuzzy rules. Then the building is simulated under different load conditions and the operating parameters are obtained from fuzzy reasoning. Finally, the effect of fuzzy strategies on energy consumption is analyzed and compared with the effects of the operating parameters obtained from simulation. The results show that energy consumption using a fuzzy regulation strategy is close to the energy consumption of knowing the exact load of the building, while the fuzzy regulation strategy can largely simplify the regulation of the airconditioning system.
A residential unit located on the first floor, facing southeast, was selected for the purpose of this study (Figure 2), with a total floor area of 53m 2 and floor to ceiling height of 2.7m. Due to the unfavourable facade orientation of the buildng (southeast) caused by the intensity of the solar gains, this makes the apartment studied a worst case scenario. An extended description of the apartment studied is included in Spentzou (2015). The building geometry was created in the simulation as a multi-zone 3D model based on the original building drawings provided by the local municipality. The simulation model includes the detailed building design and the surrounding buildings. Despite the focus of this study being a specific apartment, all floors and partitions were included in the simulations in order to compare the ventilation performance of the apartment to the other apartments. Even though the study focused on a single apartment, often, exploring the properties of a single phenomenon under specific conditions provides better understanding of the whole. The simulations were based on several assumptions/parameters (e.g. heat gains, openings, thermal mass) that were kept consistent for each of the strategies examined. Therefore, the relative performance between the natural ventilation strategies that were determined from this modelling campaign is representative of real behaviour trends.
Optimized for air and water systems. Belimo is a specialist company offering the world’s widest range of products for the motorized operation of final controlling ele- ments in HVAC systems – for air and water systems, for greater protection against fire and smoke and for the indi- vidual control of room air by means of VAV Boxes. What- ever the application, HVAC engineers will always find the optimum solution in the Belimo range.
This paper reviewed the impact of different heat mitigation strategies on the pedestrians’ thermalcomfort in the context of urban and microclimate. It should be noted that the magnitude of UHI varies in different climates. Consequently, in each climate, a specific heat mitigation strategy is needed. Most of the previous studies have investigated the changes of meteorological variables (such as air temperature deviations) by heat mitigation strategies. Among different heat mitigation strategies, vegetation and high albedo (reflective) surfaces as solutions for improving outdoor thermalcomfort in urban spaces were investigated in this paper. Vegetation was studied in the forms of parks, street trees, green roofs and green walls. High albedo materials were then studied while they are used on the roofs (as white roofs) and on the ground surfaces. Through several examples in different countries and climates, it was shown that urban surfaces play an important role on the thermalcomfort of pedestrians. Vegetation and high albedo surfaces showed appreciable reduction of air temperatures within urban open spaces. However, mean radiant temperature affects human thermalcomfort more than the other
A photovoltaic system is an array of components designed to supply usable electric power for a variety of purposes . The sun delvers its energy to us in two main forms, heat and light. There are two main types of solar power systems, namely, solar thermal systems that convert heat to electricity, and solar PV systems that convert sunlight directly into usable direct current (DC) electricity. One or more DC to alternating current (AC) power converters which called inverters. PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. Groups of cells are mounted together in panels or modules that can be mounted on your roof . The peak sun hour is essential in order to know the number of PV modules to be installed. Before doing so, the power that can be assumed generated by the PV modules must be determined based on solar irra- diance of the location.
Frequency regulation is an important ancillary service that aims to reduce instantaneous imbalance between supply and demand. To participate in the frequency regulation market, the grid assets need to be able to accurately follow the regulation signal received from RTOs (Regional Transmission Organization) every few seconds . Although an individual HVAC unit can not continuously adjust its power consumption on such a short timescale, a large number of them can take turns to contribute a small portion of the required regulation so that the entire population collectively meets the overall regulation requirement. The proposed aggregated modeling
The regular inspection task is assigned to maintenance personnel, who regularly check boiler efficiency and report a format to the local authorities. They are requested to provide sample controls on paper and on site, and can impose sanctions if maintenance and control is omitted, or the system is performing inefficiently, not respecting the minimum requirements in force at the time of purchase. A few lines are available in the reporting format for notes and recommendations, but they are usually only filled in when safety requirements are not fully satisfied (see Slovenia for heating and cooling systems, Italy for boilers, Cyprus for airconditioning systems). The level of qualification of the maintenance personnel is high, as a lot of continuous training is provided by the SME associations and their training organisations. However, they are not trained for providing recommendations, and they should be strictly supervised to avoid biased suggestions to the end users.
The first of the two arcades, the Euclid Arcade, is a one-story passage connecting two 5-story office structures. The arcade is a straight corridor 400 feet long, 15 feet wide. Constructed in the beginning of the 20th Century, around 1910, it features a double shell glass roof along its full length. Currently, the arcade operates as a mixed mode space, using air-conditioning in shops, and in the main arcade space only on days in which the temperature or humidity are excessively high. (Marcus, 2001) For the purpose of the study, the HVAC system in the mixed mode arcade was disabled throughout testing with subjects, simulating the original, naturally ventilated nature of the space.
While airconditioning is seen as a solution in some countries, alternative passive solutions could be preferable non-energy using options. These include the installation and use of shades and blinds, the provision of insulation, consideration of the orientation of rooms and the dwelling, the provision of cool rooms, and the adaptation of the urban environment to reduce reflectivity (O’Neill et al., 2009). Such passive measures to avoid over-heating need to be incorporated into the design and refurbishment of dwellings and neighbourhoods to avoid reliance on air-conditioning (Bone et al., 2010). Whatever strategies are adopted directed at protecting the susceptible groups from extreme low and high temperatures should ensure that they do not compromise occupier health in other ways such as by reducing indoor air quality (Bone et al., 2010).
It can be seen that a reduction of about 4:10% of the rated brake power from idling to 80% partial load respectively, increase in the fuel consumption by about 11:20% from idling to 80% partial load. Also, it can be seen that the results of experimental work have the same trend of the theoretical results but there are some discrepancies in some values due to the used coefficients in the theoretical model which needs some correlations and mean that the model is acceptable for presenting the engine's performance for open and closed modes.
Summer ambient temperatures in Sultanate of Oman are well known to be higher as commonly seen in other GCC countries. During summer, cars parked directly under the sun with window glass raised up, experience a very high temperature rise inside its cabin. Current research paper reports the experimental studies carried out on a parked car installed with an indigenously designed and developed cabin ventilation system powered with Solar PV energy. The experiment was carried on chosen vehicle parked at a unique direction and location exposed to day long sunlight at Muscat for considerable period of time. The experimental investigation showed that the vehicle cabin temperature was lower when ventilation system was turned on. Investigation showed that, with the ventilation system, the time taken to cool down vehicle cabin air temperature to the acceptable limit was significantly lower. With developed ventilation system the car cabin temperature reached to the comfort level much quicker, typically lesser than the half of the time compared to those values tested without ventilation system. Thus indicating, the power saving potential of the developed system as the desired level of thermalcomfort can be achieved within the shorter period of time. The reduction in time taken to cool down the cabin temperature to the acceptable limits has direct two fold effects; firstly, the fuel consumption for cooling purpose is reduced and secondly increased thermalcomfort level inside the cars cabin. However, the temperature drop pattern was not similar all around the cabin, due to the varied level of cabin sunlight exposure. Temperature drop at the front end of the car was lower than in middle and rear of the car. It was noted that when the ventilation system was turned on, the temperature inside the car was nearly 10 ºC lesser compared to cabin temperature without ventilation system.
The purpose of this study is to investigate the simulation of MATLAB® Simulink in modelling control system for air-conditioning (AC) unit and develop an adaptive control algorithm based on simulation model. Temperature control method was used as the benchmark for the proposed algorithm. A PID controller based on power consumption of AC’s installed in Jabatan Penyiaran Negeri Johor as in Table 1.1 has been proposed in this study to reduce the energy consumption of each AC unit.
neighboring thermostats. This simulated attack could possibly occur from commu- nication jamming or a denial of service attack targeting a communication module. This attack assumes the first stage of Industrial Control System (ICS) Kill-Chain has previously been completed and focuses on the second stage. ICS Kill-Chain is defined by Sans in 2015 . By compromising the peer-to-peer communication, it is effectively setting the ˜ m value to zero for any attacked thermostat. As mentioned earlier, if the ˜ m value is set to zero, the thermostat effectively reverts back to the simple thermostat model, which could lead to a dangerous rebound after a DR event. For the simulation, ˜ m is calculated through the use of the adjacency matrix of the system. The loss of communication of a thermostat from the population will be modeled by setting the row and column of the corresponding thermostat equal to zero. This act of reverting to the simple thermostat model will be recognized as a failure of the thermostat in the demand response system. Different levels of failure, or differing percent of failed nodes out of the total population, are to be tested. Using a percent of zero failure, or 100% operation, as a baseline, the different levels of failure are tested to the point that demand response is not longer effectively reducing the peakdemand of the aggregate system. Baseline simulations will be created at each population, including varying connection architectures.
Abstract: The growing number of the accessed energy-eﬀicient frequency conversion air conditioners is likely to generate a large number of harmonics on the power grid. The following shortage in the reactive power of peak load; hence; may trigger voltage collapse; and this conflicts with people’s expectations for a cozy environment. Concerning the problems mentioned above; an active management scheme is put forward to balance the electricity use and the normal operation of airconditioning systems. To be specific; firstly; schemes to suppress the low voltage ride through (LVRT) and harmonic are designed. Then to deaden the adverse effects caused by nonlinear group load running on the grid; and to prevent the unexpected accidents engendered from grid malfunction; the dynamic sensing information obtained by an online monitor is analyzed; which can be seen as active supervise mechanism. The combined application of active and passive filtering technology is studied as well. Thirdly; the new energy storage is accessed reliably to cope with peak- cutting or grid breaking emergencies; and the fuzzy control algorithm is researched. Finally; system feasibility is verified by functional modules co-operation simulation; and active management target is achieved under scientific and reasonable state-of-charge (SOC) management strategy
high rise buildings. Second, asymmetric distribution for the buildings which leads to big open space between the buildings, this means the shading from the tall buildings to each other is lost. The long distances between the buildings would create a big space of surface ground could absorb heat and keep it along daytime. The results that are obtained for mean radiant temperature indicated that the minimum values of the mean radiant temperature could be observed in the (SJP) model as shown in Fig. 17, because of the effect of the shadings that are obtained from the existence of the pergolas along the path (A-B) of the pedestrians and the effect of the shadow from the trees. The maximum decrease in values of mean radiant temperature reaches to 35℃ on the path (A-B) that are recorded in the Sophora Japonica around pergolas of the pedestrians (SJP). The reason is attributed to the presence of the shading and the decreases for emitting of the long wave radiation from the surfaces of buildings and the grounds. The surface temperature of urban facades is the primary factor that could contribute to reducing thermalcomfort. The results of grass and trees (GT) model are almost convergent to the Base model due to lack of shadings which enhanced to decrease the values of mean radiant temperatures. Shadows, which are obtained from (PAB) model was not enough on improving the results of mean radiant temperature comparing with the Base model results.