Shine The Light Only When Needed

If you work at Toronto Western Hospital or if you have visited the site, you may know that we have an underground 2-level parking garage below Fell Pavilion.  To provide enough lighting for drivers, 21 powerful 250W high pressure sodium (HPS) lighting fixtures were installed on parking garage entrance ramp sidewall, some are outside and some are inside.  Those lighting fixtures share a few circuits together so the only way to run the outside ones is to keep all the lights on 24/7.  As an energy project manager I felt guilty every time I passed by the ramp area.

HPS was invented by GE in 1960s. The bulb contains a small amount of solid sodium inside a glass tube. When heated up the sodium would vaporize and the lamp would glow yellow.  Typical construction is shown as below:


HPS has higher efficiency when compared with Continue reading

Cooling Tower Repair at Toronto Western Hospital

Have you ever imagined hospital shutdown in the middle of summer?  It is possible if Continue reading

Cooling Tower Winter Operation at Toronto Western Hospital

Last time we talked about chilled water system upgrade at TWH.  The chilled water is pumped to various mechanical rooms to cool air supplied to the hospital, medical equipment such as MRIs and some local refrigeration machines.  Then it comes back to the central chiller plant and is cooled down by the chillers.  The chillers use refrigerant to transfer the heat from the building to condenser water side.  You may be curious where the huge amount of heat removed from the hospital goes.  The answer is Continue reading

Variable Flow Chilled Water System Upgrade At Toronto Western Hospital

At Toronto Western Hospital, the central chilled water system provides building cooling and process cooling for the whole site. It’s capable of providing astonishing 4800 ton cooling capacity. Each ton of cooling capacity is the energy needed to melt 2000 lbs of 0°C ice within one hour. That’s enough to cool about 1,200 houses! The 3 chilled water pumps are the largest at UHN rated at 200 horsepower (hp), 250 hp and 250 hp respectively.

Figure 1 One cooling ton is the energy needed to melt 2000 lbs of ice at 0°C.

Figure 1 One cooling ton is the energy needed to melt 2000 lbs of ice at 0°C in 1 hour.

Every summer, Angelo Bruni, Facilities Manager and his team would scratch their heads about Continue reading