Showing papers on "Cooling load published in 2007"
TL;DR: In this article, the authors investigated previous work on thermal energy storage by incorporating phase change materials (PCMs) in the building envelope and showed that with suitable PCMs and a suitable incorporation method with building material, LHTES can be economically efficient for heating and cooling buildings.
580 citations
TL;DR: In this paper, the impact of using cool roof coatings on cooling and heating loads and the indoor thermal comfort conditions of residential buildings for various climatic conditions is estimated, and the results show that increasing the roof solar reflectance reduces cooling loads by 18-93% and peak cooling demand in air-conditioned buildings by 11-27%.
478 citations
TL;DR: In this article, an experimental investigation and analysis of the energy and environmental performance of a green roof system installed in a nursery school building in Athens is presented and analyzed, while in the second one the energy savings were examined through a mathematical approach by calculating both the cooling and heating load for the whole building as well as for its top floor.
292 citations
TL;DR: In this article, the authors used an Artificial Neural Network (ANN) model to predict location specific hourly temperatures for London, taking into account radial distance from central London, hourly air temperature measured at the meteorological station and associated synoptic weather data.
168 citations
TL;DR: A coupled model consisting of a multilayer urban canopy model and a building energy analysis model has been developed to investigate the diurnal variations of outdoor air temperature in the office areas of Tokyo, Japan as discussed by the authors.
Abstract: A coupled model consisting of a multilayer urban canopy model and a building energy analysis model has been developed to investigate the diurnal variations of outdoor air temperature in the office areas of Tokyo, Japan. Observations and numerical experiments have been performed for the two office areas in Tokyo. The main results obtained in this study are as follows. The coupled model has accurately simulated the air temperature for a weekday case in which released waste heat has been calculated from the energy consumption and cooling load in the buildings. The model has also simulated the air temperature for a holiday case. However, the waste heat from the buildings has little influence on the outdoor temperatures and can be neglected because of the low working activity in the buildings. The waste heat from the air conditioners has caused a temperature rise of 1°–2°C or more on weekdays in the Tokyo office areas. This heating promotes the heat-island phenomenon in Tokyo on weekdays. Thus, it is ...
161 citations
TL;DR: In this paper, a transient and implicit model based on numerical heat transfer and computational fluid dynamics was developed to predict the thermal performance and cooling capacity of earth-air-pipe systems.
131 citations
TL;DR: In this paper, the basic parameters and the energy flows of a ground source heat pump system (GSHP) used for air conditioning the New City Hall of Pylaia (Thessaloniki area, Northern Greece).
124 citations
Patent•
18 Dec 2007
TL;DR: A cooling system for providing conditioned air to a facility includes a chiller or other cooling subsystem, a cooling tower subsystem and one or more air handling units or process cooling units as mentioned in this paper.
Abstract: A cooling system for providing conditioned air to a facility includes a chiller or other cooling subsystem, a cooling tower subsystem and one or more air handling units or process cooling units. The cooling subsystem may advantageously include one or more chillers (e.g., variable speed chillers, constant speed chillers, absorption chillers, etc.) and chilled fluid pumps. The cooling tower subsystem includes one or more cooling tower units and condenser fluid pumps. In some implementations, the air handling unit has a cooling coil and a variable volume fan. In some implementations, direct expansion (DX) cooling systems comprise compressors, evaporators and air-cooled, water-cooled or evaporatively-cooled condensing systems. Such systems can be controlled to reduce energy waste, improve occupant comfort and/or improve the thermal characteristics of the process cooling unit. The cooling system further comprises a control system which is configured to evaluate a cooling load value at the air handling unit and use the cooling load value to calculate at least one operational setpoint. The operational setpoint may advantageously be selected to improve the energy efficiency of the overall cooling system.
112 citations
TL;DR: In this paper, the authors investigated the shading effects due to nearby obstructions when daylighting schemes are being employed and found that shading effects strongly affect the building's energy budget when using daylighting designs.
110 citations
TL;DR: In this article, a feasibility study on the utilization of ocean thermal energy in Dalian is presented, where the economic, energy and environmental impacts are analyzed, and a series of sensitivity analyses are undertaken to investigate the magnitude of the effect of the parameters variation on cost calculation.
107 citations
TL;DR: In this paper, the effect of building orientation, facade construction, special roof system and window shading device on indoor thermal environment and cooling load was studied to evaluate the effectiveness of various passive climate methods.
TL;DR: Wang et al. as discussed by the authors used phase change materials (PCM) as a pre-condenser in a refrigeration system to reduce the temperature of the sub-cooled refrigerant and stabilize the superheat.
TL;DR: In this article, a method is proposed for estimating the electricity consumption and associated carbon emissions of a defined electrical-lighting configuration in an office building, accounting for the daylight contribution from windows and rooflights.
TL;DR: In this paper, the performance of floor-supply displacement ventilation with swirl diffusers or perforated panels under a high cooling load (nearly 90 W/m2) was investigated.
TL;DR: In this article, a numerical simulation of the temperatures distribution of an office placed in Milan, Italy, during the month of July, is conducted on a Simulink® dynamical model.
TL;DR: In this article, the inherent operational characteristics of a direct expansion (DX) A/C unit at a fixed inlet air state when the speeds of both its compressor and supply fan are varied are investigated.
TL;DR: In this article, micro gas turbines were used to meet the electrical, domestic hot water, heating and cooling energy needs of a residential building located in Tehran, Ahvaz and Hamedan.
TL;DR: In this article, the authors investigated the part load performance of the air-cooled centrifugal chillers via a thermodynamic model and validated the model using a wide range of operating data from an existing chiller with specific settings of outdoor temperature and condensing pressure in controlling the condensing temperature.
TL;DR: In this article, a computer program was developed for simulating the effect of various parameters on cooling load of the buildings in hot and humid regions in South of Iran during the peak load period of the year (July-August).
TL;DR: Based on the part load performance curves of air-cooled screw chillers, it is ascertained that for two equally sized chillers operating, one should carry a full load and the other should be partially loaded to meet the system load as mentioned in this paper.
TL;DR: In this paper, a near-optimal control method was developed for charging and discharging of cooling storage systems when real-time pricing (RTP) electric rates are available.
Abstract: A near-optimal control method was developed for charging and discharging of cool storage systems when real-time pricing (RTP) electric rates are available The algorithm requires relatively low-cost measurements (cooling load and storage state of charge), requires very little plantspecific information, is computationally simple, and ensures that building cooling requirements are always met (e.g., storage isn't prematurely depleted). The control method was evaluated for ice storage systems using a simulation tool for different combinations of cooling plants, storage sizes, buildings, locations, and RTP rates. The simplified method worked well in all cases and gave annual costs within approximately 2% of the minimum possible costs associated with optimal control.
TL;DR: In this article, a reinforcement learning controller learns to operate the building and cooling plant based on the reinforcement feedback (monetary cost of each action, in this study) it receives for past control actions.
Abstract: This paper describes an investigation of machine learning for supervisory control of active and passive thermal storage capacity in buildings. Previous studies show that the utilization of active or passive thermal storage, or both, can yield significant peak cooling load reduction and associated electrical demand and operational cost savings. In this study, a model-free learning control is investigated for the operation of electrically driven chilled water systems in heavy-mass commercial buildings. The reinforcement learning controller learns to operate the building and cooling plant based on the reinforcement feedback (monetary cost of each action, in this study) it receives for past control actions. The learning agent interacts with its environment by commanding the global zone temperature setpoints and thermal energy storage charging/discharging rate. The controller extracts information about the environment based solely on the reinforcement signal; the controller does not contain a predictive or system model. Over time and by exploring the environment, the reinforcement learning controller establishes a statistical summary of plant operation, which is continuously updated as operation continues. The present analysis shows that learning control is a feasible methodology to find a near-optimal control strategy for exploiting the active and passive building thermal storage capacity, and also shows that the learning performance is affected by the dimensionality of the action and state space, the learning rate and several other factors. It is found that it takes a long time to learn control strategies for tasks associated with large state and action spaces.
TL;DR: In this paper, the authors developed a new example weather year and a mathematical model to generate design occupant load profiles using Monte Carlo simulation for a subtropical climate, which would be useful for determining the HVAC energy consumption in buildings in order to obtain more representative data for the prediction of annual energy consumption.
TL;DR: In this paper, an attempt is made to investigate the impact of the urban heat island (UHI) effect on the energy consumption of a building using both, an accurate, extensively validated, transient simulation model and a neural network one.
TL;DR: Based on the time schedule of air conditioning use of Taipei citizens, the heat rejection/building energy use and the air temperature distribution were evaluated, and finally the additional electric consumption of air conditioners was predicted.
TL;DR: In this article, the authors developed a simulation model for analyzing the performance of a water-LiBr solar assisted absorption system with an auxiliary heating source and examined the effects of clearness index on the auxiliary heating requirements.
TL;DR: In this article, an open desiccant cooling process is presented and applied to ventilation and recirculation modes of the system operation, where ideal operating characteristics based primarily on the first law of thermodynamics are assumed for each component.
TL;DR: In this article, the authors investigated the effect of heat-pipe air-handling coil on energy consumption in a central air-conditioning system with return air and showed that compared with conventional central airconditioning systems with return-air, the heatpipe air conditioning system can save cooling and reheating energy.
Patent•
19 Jun 2007
TL;DR: In this paper, a proportional band was used to adjust capacity to compensate for changes in heating or cooling load, and the proportional band is adjusted to bring the actual temperature within the space closer to the set point temperature.
Abstract: Relatively constant temperatures are maintained in a space by varying the capacity of heating or cooling equipment. A proportional band is used to adjust capacity to compensate for changes in heating or cooling load, and the proportional band is adjusted to bring the actual temperature within the space closer to the set point temperature. Such an adjustment may be made by determining the difference between the present temperature and the set point temperature, and adjusting a floating temperature set point by a percentage (e.g., ten percent) of the difference. Such a process may be repeated, for example, at regular intervals, such as once per minute. As a result, the temperature within the space approaches (e.g., asymptotically) the set point temperature whether the heating or cooling load is high or low. Methods, systems, and apparatuses are contemplated, including HVAC units and controls, including for residential applications, including using variable-speed drives.
TL;DR: In this paper, the authors investigated whether the glass curtain walls are appropriate for the Tunisian local climate and context and if it is so, to give recommendations concerning the kind of glass to be used.