The Demands of P3s
British Columbia’s first pUBLIC-Private partnership (P3) acute care hospital was the largest project completed to date in British Columbia’s Fraser Valley. It also challenged the design team with the strictest energy requirements...
Business & Professional
Building Mechanical & Electrical (HVAC) Systems
British Columbia’s first pUBLIC-Private partnership (P3) acute care hospital was the largest project completed to date in British Columbia’s Fraser Valley. It also challenged the design team with the strictest energy requirements ever specified for a similar facility.
The $355-million Abbotsford Regional Hospital and Cancer Centre (ARHCC) east of Vancouver is a 60,000-sq.m complex offering 300 acute care beds, nine operating theatres, maternity and pediatric services, medical imaging, radiation cancer treatment, and a host of secondary staff and patient services. The design called for 25 per cent energy efficiency over a typical code-compliant hospital — an energy requirement that was unparalleled at the time of tender.
Access Health Abbotsford (AHA) is the P3 consortium that was selected to complete design, construction, financing and maintenance of the facility over the next 30 years. As a P3 contract, the facility’s operating energy cost guarantee was subject to risk/reward consequences. If the upper limit of the energy guarantee were exceeded, AHA would have to pay the excess through one of its consortium members, Johnson Controls, which is operating the facility.
The P3 arrangement made it absolutely critical to have realistic and reliable pre-construction energy calculations. Meeting those calculations was the biggest challenge presented by the project, says Paul Marmion, P.Eng., senior principal with Stantec. Stantec was the mechanical consulting engineer and engineer of record for the hospital’s HVAC, plumbing and fire protection.
“The original P3 contract stipulated that the hospital be a LEED certified project and qualify for at least three LEED energy credits,” Marmion says. “At the time of the original bid process, this was a very aggressive target that no green site acute care hospital had achieved, to our knowledge.”
Adding to the challenge, the bid construction cost was over the owner’s budget, meaning the energy saving strategies also had to have a fast payback and minimal capital cost.
“Because of the 30-year operating requirement and the energy operating cost guarantees, the P3 bid team was very much averse to risk, so all energy saving strategies had to be proven technology with long-term reliability and repeatability,” says Marmion.
“For example, using Abbotsford aquifer water for heat pump heating and cooling could have been an easy way to achieve the three energy credits with a fast payback, but it was considered by the P3 team to be too risky.”
Systems to achieve required LEED energy credits
The design team worked closely with Curt Hepting, P.Eng., of EnerSys Analytics, using a modified DOE2e software tool to perform complex energy and cost analysis on various energy saving strategies.
“The output specification defined the number of LEED energy credits that the design had to meet, which effectively defined the required energy efficiency,” says Marmion. “It was the team’s responsibility to design the hospital to meet the energy targets.”
The building uses variable air volume (VAV) reheat in most areas, constant volume (CV) in critical care areas, and some radiant heating throughout.
The design team selected two 4,900 kW and one 2,000 kW high-efficiency gas-fired hot water boilers and located them in a centralized energy centre.
A flue gas heat recovery system uses a heat exchanger located in the combined boiler breeching, which recovers up to 700 kW of energy that would normally be wasted. The recovered energy is used for building reheating loads and domestic hot water heating.
The incremental capital cost of adding the flue gas heat recovery system was $208,000, with a predicted annual energy saving of $36,000, providing a 5.8-year simple payback.
The hospital’s high-efficiency chilled water generation system comprises two 900-ton chillers piped in a counter-flow configuration with chilled water temperature reset control. The chillers optimize energy efficiency, consuming a maximum of 0.5 kW/ton of cooling.
“There was no incremental capital cost of adding the counter-flow configuration,” says Marmion, “resulting in an annual energy saving of $3,400, and providing instant pay back.”
A condenser water heat recovery system recovers up to 980 kW of the energy that would normally be wasted and uses it for heating incoming domestic hot water up to 85ºF. The team achieved a simple six-month payback on the system with a $15,000 capital investment and annual energy savings of $28,000.
An exhaust air heat recovery system recovers energy from all of the building’s significant exhaust air systems and uses it to reduce the energy impact of the large, outside air systems that serve the operating rooms, laboratory and intensive care areas.
Variable speed control is used on all significant fans and circulating pumps. Bypass control on all heat recovery and cooling coils reduces stand-by energy losses. The dampers save $1,200 per year and provide a six-year simple payback.
Addressing occupancy loads, demand ventilation controls use CO2 and occupancy sensors to control the amount of ventilation air supplied to non-critical areas of the hospital.
In the building’s large three-storey high atrium space, vents at low and high levels are automatically opened and closed as required to supplement the mechanical ventilation system, creating an integrated natural and mechanical system for optimal air quality and ventilation. To achieve this, the team performed a computational fluid dynamics (CFD) analysis to confirm air flow rates and thermal comfort under various outside and inside operating conditions.
Factory fabrication and testing were used on major equipment such as air handling units (AHUs). Meanwhile, flexible HVAC systems were developed for medical equipment that was ordered “just in time” to ensure the most advanced technology was available and selected.
Because acoustic insulation was not used in any supply or return air ductwork so as to limit any potential contamination of the supply air, an acoustic consultant had to determine the best selection and installation of AHUs and terminal units. Sound attenuators and double layers of drywall rap were used as acoustic cladding in noise-sensitive areas.
The air handling plant is mainly located at roof level, using 21 factory-fabricated AHUs, serving 1,200 variable air volume boxes with non-typical configurations. Non-typical rooftop primary ducting and piping configurations were used to accommodate the construction schedule, budget, and tight floor-to-ceiling constraints.
Lighting, building envelope,
and plumbing all play a part
“Low flow plumbing fixtures reduce the energy required to heat the domestic hot water, saving $24,000 in energy costs annually,” says Marmion. As well, “Energy efficient light systems with lighting power density of 8.9 W/m2 compare with typical hospital systems having a lighting power density of 15.3 W/m2.”
The high-performance building envelope uses low-e, argon-filled glazing and coating to control the building’s heating and cooling loads. Payback on the building envelope is expected within one year.
The project was also constrained by a fast-track timeframe, requiring the design and construction team to rethink typical hospital design and construction practices, starting with a fully integrated process, and with quality control throughout design and construction phases.
The hospital qualified for 11 environmental quality LEED credits, including those meeting ASHRAE Standards 55 and 62.1, those for controlling tobacco smoke, CO2 monitoring and control, and indoor air quality construction management control.
Uses less than half the energy
of a typical Vancouver hospital
As an initial point of comparison, EnerSys Analytics entered the
building characteristics and billed data for the second year of operation into the company’s Energy Profile Tool. The tool provides estimated end-use energy information as well as a benchmark derived from default indicators from the U.S. Environmental Protection Agency’s Energy Star Portfolio Manager.
“After the second year of operation, billing data indicate that ARHCC was running at 153 kBtu/ft², compared with a typical Vancouver hospital’s energy use intensity of about 350 kBtu/ft²,” says Hepting.
The tool also indicated that ARHCC’s annual CO2 production of 3,140 metric tons is less than half a comparable facility, achieving CO2 savings equivalent to taking 1,400 cars off of the road.
“EnerSys Analytics also entered specific information and billing data directly into the EPA’s Portfolio Manager to check the relative Energy Star indicators, adjusted for the specific project conditions,” says Hepting. “After the second year of operation, the Energy Star system performance indicated the energy intensity at 42% below the U.S. National Average — equivalent to a rating of 93 out of a possible maximum of 100.”
Natural Resources Canada (NRCan) indicates the average hospital energy use in Canada is 2.65 GJ/m², equalling 233 Btu/ft² — a number still significantly higher than the ARHCC’s utility bills.cce
Jessica Krippendorf is a freelance writer in Vancouver Island. B.C.
Abbotsford Regional Hospital and Cancer Centre
Mechanical: Stantec Consultants (Paul Marmion, P.Eng.).
Electrical: RADA (Doug Redmond, P.Eng.)
Energy analysis: EnerSys Analytics (Curt Hepting, P.Eng.)
P3 Consortium/design, construction, financing and
maintenance 30 years: Access Health Abbotsford (AHA). John Laing Investments Abbotsford (project manager); ABN AMRO Bank N.V (finance/development); PCL Constructors Westcoast (design-build contractor); MCM/Silver Thomas Hanley (design services); Johnson Controls/Sodexho (facility management).