تغییر نرخ های تهویه در دفاتر آمریکا: مفاهیم سلامت، عملکرد کار، انرژی، و اقتصاد مرتبط

This paper provides quantitative estimates of benefits and costs of providing different amounts of outdoor air ventilation in U.S. offices. For four scenarios that modify ventilation rates, we estimated changes in sick building syndrome (SBS) symptoms, work performance, short-term absence, and building energy consumption. The estimated annual economic benefits were $13 billion from increasing minimum ventilation rates (VRs) from 8 to 10 L/s per person, $38 billion from increasing minimum VRs from 8 to 15 L/s per person, and $33 billion from increasing VRs by adding outdoor air economizers for the 50% of the office floor area that currently lacks economizers. The estimated $0.04 billion in annual energy-related benefits of decreasing minimum VRs from 8 to 6.5 L/s per person are very small compared to the projected annual costs of $12 billion. Benefits of increasing minimum VRs far exceeded energy costs while adding economizers yielded health, performance, and absence benefits with energy savings.

Cost-benefit analysis, Economizer, Health, Office, Ventilation rate, Work performance,

How much outdoor air ventilation should be provided to buildings? Providing more ventilation increases building energy consumption, increases the related emissions of carbon dioxide, and contributes to climate change. Modeling of the U.S. commercial building stock [1] indicates that 6.5% of all end-use energy (3.2% in offices) is for heating and cooling of mechanically-supplied outdoor air ventilation. Using the data in [1], one can estimate that an additional 3% of total end-use energy is used to heat and cool infiltration air, thus, an estimated 9.5% of end-use energy is required for ventilation. From an energy and climate change perspective, we want to reduce ventilation rates. However, providing less ventilation increases indoor concentrations of many indoor-generated air pollutants, although indoor concentrations of some outdoor air pollutants are decreased. In offices, for which the largest amount of data are available, higher VRs are associated with greater satisfaction with indoor air quality, fewer SBS symptoms, and improved work performance [2], [3] and [4]. Limited research also indicates that higher VRs are associated with reduced absence rates in offices [5] and schools [6], possibly because providing more ventilation may reduce transmission of infectious respiratory illnesses [7]. Despite the long-standing debate about the correct values for minimum VRs, there have been few attempts to quantitatively compare the benefits and costs of ventilation. The minimum VRs specified in existing and most older standards for commercial buildings are based primarily on decades-old laboratory studies showing that 80% of unadapted occupants were satisfied with air quality with a VR of about 7.5 L/s per person in a situation with people as the primary indoor pollutant source [8]. The current U.S. ventilation standard for offices [9] maintains approximately this same minimum ventilation rate if the building has a default (typical) occupant density but divides the minimum ventilation requirement into two components, one a minimum rate of outdoor air supply per occupant and the second a minimum rate of outdoor air supply per unit floor area. Today, we have more information to consider when setting standards, particularly for office buildings. Accordingly, this paper provides quantitative estimates of benefits and costs of providing different amounts of outdoor air ventilation in U.S. offices. The estimates should be of value for decisions about building operation and setting of minimum ventilation rate standards