The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipme...The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipment such that the temperature of hot water supply is maintained at a set-point that may be a fixed value or be compensated against the external temperature. This paper presents a novel scheme that can determine the optimal set-point of hot water supply that maximizes the energy efficiency whilst providing sufficient heating capacity to the load. This scheme is based on Adaptive Neuro-Fuzzy Inferential System. The aim of this study is to improve the overall performance of district heating systems.展开更多
Tall buildings in cold climates have unique challenges in maintaining indoor air quality due to stack effect.During the heating season,interior air buoyancy creates large pressure differentials in vertical shafts that...Tall buildings in cold climates have unique challenges in maintaining indoor air quality due to stack effect.During the heating season,interior air buoyancy creates large pressure differentials in vertical shafts that can drive airflow from lower floors into upper floors.This pressure differential can result in the spread of contaminants throughout a building.Most recently,concern over COVID-19 has increased attention to the potential spread of airborne diseases in densely populated buildings.For many multi-unit residential buildings,suite ventilation has traditionally relied upon fresh air supplied through a mechanically pressurized corridor.In cold climates,large pressure differentials created by stack-effect can reduce the effectiveness of this approach.Multizone and CFD simulations are employed to analyze airflow and contaminant spread due to stack effect.Simulations are conducted on an idealized model of a 10-storey building using a range of experimentally derived airtightness parameters.Simulations demonstrate stack effect can reduce corridor ventilation to suites and even reverse the airflow for leakier buildings.Reduced airflow to suites can result in the accumulation of contaminants.Reversal of the airflow can allow contaminants from a suite to spread throughout the building.Contaminant spread is illustrated as a function of mechanical ventilation,building airtightness,and ambient temperatures.Strategies to reduce the influence of stack effect on mechanically pressurized corridors are discussed.展开更多
文摘The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipment such that the temperature of hot water supply is maintained at a set-point that may be a fixed value or be compensated against the external temperature. This paper presents a novel scheme that can determine the optimal set-point of hot water supply that maximizes the energy efficiency whilst providing sufficient heating capacity to the load. This scheme is based on Adaptive Neuro-Fuzzy Inferential System. The aim of this study is to improve the overall performance of district heating systems.
基金supported by the Natural Sciences and Engineering Research Council of Canada[NSERC DG 2016-04176].
文摘Tall buildings in cold climates have unique challenges in maintaining indoor air quality due to stack effect.During the heating season,interior air buoyancy creates large pressure differentials in vertical shafts that can drive airflow from lower floors into upper floors.This pressure differential can result in the spread of contaminants throughout a building.Most recently,concern over COVID-19 has increased attention to the potential spread of airborne diseases in densely populated buildings.For many multi-unit residential buildings,suite ventilation has traditionally relied upon fresh air supplied through a mechanically pressurized corridor.In cold climates,large pressure differentials created by stack-effect can reduce the effectiveness of this approach.Multizone and CFD simulations are employed to analyze airflow and contaminant spread due to stack effect.Simulations are conducted on an idealized model of a 10-storey building using a range of experimentally derived airtightness parameters.Simulations demonstrate stack effect can reduce corridor ventilation to suites and even reverse the airflow for leakier buildings.Reduced airflow to suites can result in the accumulation of contaminants.Reversal of the airflow can allow contaminants from a suite to spread throughout the building.Contaminant spread is illustrated as a function of mechanical ventilation,building airtightness,and ambient temperatures.Strategies to reduce the influence of stack effect on mechanically pressurized corridors are discussed.
