ASHRAE Journal - November 2011 - 45

technology award case studies
Before Production Productivity Natural Gas Consumption Electricity Consumption Pounds of Linen Annually Pounds of Linen/Hours Worked Therms Therms/lb of Linen kWh kWh/lb of Linen 18,171,364 108.07 605,984 0.033 4,312,700 0.237 After 21,882,983 134.08 496,690 0.023 4,031,500 0.184 Difference 20% 24% –18% –32% –7% –22%

Building at a Glance
Name: Buanderie Centrale de Montréal Location: Montreal Owner: Agence de la santé et des services sociaux de Montréal Principal Use: Laundry Services Includes: Administrative Area Employees/Occupants: 122

Table 1: Results of the modernization project.
Before Total Fresh Air Supply Total Air Supply Total Fans Power 60,000 cfm 165,000 cfm 155 hp After 20,000 cfm 80,000 cfm 105 hp Difference –67% –52% –32%

Gross Square Footage: 111,000 Conditioned Space: 107,250 Substantial Completion/Occupancy: 2009 National Distinctions/Awards: AICQ’S Léonard 2010, Consulting Engineering Next Generation category

Table 2: Airflow comparison, original design vs. new design. the equipment indoors made maintenance easier, especially in winter. Codes and engineering good practices also have changed. Quebec provincial health-care and workers regulations speciﬁed that extra rest periods are required if the indoor wet-bulb globe temperature is higher than 86°F (30°C). Extra rest periods could be as long as 45 minutes every hour, reducing productivity in a signiﬁcant way. This requirement was not included in the original design. Space had to be found to include new cooling devices to provide air at a temperature lower than the maximum allowed by regulation—without an increase in annual energy costs. Energy recovery equipment was added to the project to compensate for the energy consumption by the cooling system in summer.
IAQ and Ventilation

The BCM production area is about 100,000 ft2 (9290 m2) and separated into three areas: receiving and washing, drying, and ﬁnishing and shipping. To limit the dispersion of odors and contaminants, the receiving and washing area must be at
November 2011

a negative pressure with regard to the rest of the areas of production. To do so, fresh air is introduced in the building at the ﬁnishing and shipping area and exhausted at the receiving and washing area. Air is transferred from the “cleaner area” to the “dirtier” and follows the inverse path of the washing process. Original ventilation systems were sized to evacuate the heat rejection of production equipment, mainly steam and natural gas dryers and steam ironers. In Montreal in the summer, outdoor air temperature could be higher than 90°F (32°C). Even with a high fresh airﬂow, it is hard to maintain an adequate indoor temperature for workers, if the fresh air supply is not cooled. Also, these original ventilation systems were designed at constant ﬂow. Heating power demand was important, adding important costs to the annual energy bills. Furthermore, no humidiﬁcation was provided in winter. The production area humidity was speciﬁed using ASHRAE Standard 55-2004. All these concerns were addressed in the modernization project. New ventilation design provided a better indoor

environment at lower energy costs. Air supply was designed for the occupants’ needs instead of the requirements of the equipment. More than 90% of the employees work in the ﬁnishing and shipping area (last area of the washing process). It is in this 40,000 ft2 (3716 m2) area that fresh air is introduced in the building. The main air-handling unit (AHU) supplies 40,000 cfm (18 878 L/s) with 50% fresh air and includes a cooling coil, a “face and bypass” steam coil and a steam humidiﬁer. Since heating demand was reduced, there was no need for an extra boiler in the project. Existing steam boilers have the capacity to supply all process equipment and the main AHU. Also, in winter, the humidity rate is at 30% when indoor temperature is between 68°F and 73°F (20°C and 23°C), which meets ASHRAE Standard 55. Air is transferred from the ﬁnishing and shipping area toward the drying area.
ASHRAE Journal 45

ASHRAE Journal - November 2011

Table of Contents for the Digital Edition of ASHRAE Journal - November 2011