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Generic design strategies for energy-efficient, low-carbon buildings
Published in Paul Tymkow, Savvas Tassou, Maria Kolokotroni, Hussam Jouhara, Building Services Design for Energy-Efficient Buildings, 2020
Paul Tymkow, Savvas Tassou, Maria Kolokotroni, Hussam Jouhara
A further consideration for carbon mitigation strategies is to minimise ‘unregulated’ or ‘uncontrolled’ and ‘process’ loads. The terminology is not always consistent, but ‘unregulated’ loads usually covers loads such as electronic equipment in offices, data processing or computer installations, audio-visual, catering and other equipment that can be deemed to be part of the business or activity processes, rather than fixed building services systems ‘servicing’ the occupied spaces in the building. Where the loads are specific systems or installations such as data centres or catering facilities, they are often called ‘process loads’. Where there are miscellaneous loads fed from the small power system, they are often called ‘plug loads’ (particularly in the United States). These loads receive little attention in regulatory frameworks. While this can help to focus attention on the fixed building services systems, it can be seen from Figures 3.5 and 3.6 that some process loads (computing and catering) can be significant. Moreover, unregulated loads will contribute to the internal gains in spaces, and hence potentially the energy demand for cooling and ventilation. To be fully effective, energy and carbon reduction strategies (especially management regimes) should also seek to address uncontrolled and process loads.
Green Smart Buildings for Smart Cities
Published in Pradeep Tomar, Gurjit Kaur, Green and Smart Technologies for Smart Cities, 2019
Dushyant Singh Chauhan, Gurjit Kaur
Significant portions of the overall energy usage of a building generally comprises plug and process loads. These loads are often not directly correlated with general electrical lighting or cooling systems and usually do not offer comfort to the residents in any form. These plug loads arise from equipment that is plugged in and used by the residents, such as microwaves, refrigerators, printers, computers, wall-projectors, vending machines, mobile chargers, audio equipment and so on. Therefore, there are enormous opportunities to understand and manage these type of loads. The key challenge in dealing with plug loads can arise from the changing needs of the residents, and the usage patterns are often unknown.
Sensor Networking Software and Architectures
Published in John R. Vacca, Handbook of Sensor Networking, 2015
Sensors are a critical component of smart buildings. Effective control depends on knowing the operational status of the building at fine temporal and spatial granularities. Three important variables that should be monitored are occupancy and user context, environmental conditions, and energy usage: Occupancy and user context: Passive infrared (IR) sensors are the most common type of sensors in modern buildings but suffer from accuracy problems because they are actually motion sensors. False positives (when the sensor detects a person who is not actually there) and false negatives (when the sensor fails to detect a person) are common (Weng and Agarwal 2012). In addition to occupancy, user context is useful information to measure if feasible. For example, knowing whether users are actively using devices can lead to better policies for plug-load device control.Environmental sensing: Most modern buildings have a BMS that monitors temperatures and other variables for the zones in a building. This information is important for optimizing control over HVAC settings.Energy sensing: Two broad classes of plug-load energy detection are direct sensing, which connects a meter directly in-line with the plug-load device, and indirect sensing, which attempts to measure energy usage without attaching a meter to every device. Direct methods are more accurate than indirect methods, although indirect methods are generally easier to deploy. Nonintrusive load monitoring began with an attempt to disambiguate energy loads from a central energy meter (Hart 1992), while more recent approaches use learning algorithms. Indirect sensing approaches have used sensors to detect the magnetic field variations that occur near plug-load devices.
Tradeoffs between energy use and ventilation rates in U.S. Retail stores
Published in Science and Technology for the Built Environment, 2020
Zuhaira Alhafi, Jelena Srebric
The two studied big-box retail stores are located in central Pennsylvania in the U.S. climate zone 5 (moderate to cold climate). The envelope of these buildings is medium weight. Window and door glazing area represents only 10% of the total wall area. Plug loads include equipment such as lighting exhibitions, computers, refrigerators, freezers. Both stores were air conditioned and mechanically ventilated with direct expansion rooftop units (RTU) systems. Electrical cooling is used for summer and gas is used for heating. Store 1 is a one-story general merchandise store with a floor space area of 11,300 m2 (122,000 ft2) with 83% retail area, and its volume is 66,800 m2 (2,360,000 ft³). Retail store 2 is a one–story general merchandise store with a floor space area of 16,600 m2 (178,000 ft2) with 94.8% retail area and its volume is 99,500 m2 (3,510,000 ft³). There is a total of 23 and 44 Constant Air Volume (CAV) RTUs for retail store 1 and 2, respectively. The working hours for the stores are 11 hours for the store 1, and 24 hours for the retail store 2.
Equipment power consumption and load factor profiles for buildings’ energy simulation (ASHRAE 1742-RP)
Published in Science and Technology for the Built Environment, 2018
Plug loads are one of the main contributors to overall modern building power consumption (Sheppy et al. 2011). This is partly due to their increased use and increased power demand in the information technology field. In addition, design approaches, codes, and efficiency improvement programs focus mainly on other end uses like lighting and heating, ventilation, and air conditioning (HVAC) loads. Plug loads now consume up to 50% of the total electricity consumption of buildings with high-efficiency HVAC systems (New Buildings Institute 2012). Plug loads are the electrical loads that are plugged directly into an electrical outlet. Plug loads do not include large appliances, general building lighting, heating and ventilation, cooling, or water heating systems (Moorefield et al. 2008).
Update to office equipment diversity and load factors (ASHRAE 1742-RP)
Published in Science and Technology for the Built Environment, 2018
Omer Sarfraz, Christian K. Bach
The HVAC community focuses on improving The energy efficiency of heating, ventilation, and air-conditioning (HVAC) systems and on developing better building envelope systems. In the past years, this has substantially decreased heating and cooling loads, as well as the associated electricity and heating fuel consumption. Plug loads are now one of the main contributors to overall modern building power consumption (Sheppy et al. 2011). Plug loads are the electrical loads that are plugged directly into an electrical outlet. Plug loads do not include large appliances, general building lighting, heating and ventilation, cooling, or water heating systems (Moorefield et al. 2008).