Through our experience in central energy plant design in numerous industry sectors, we believe that sustained successful outcomes stem from proactive engagement with our clients’ unique requirements. This commitment extends beyond the construction stage and well into a building’s lifecycle and the operations and maintenance aspects of its systems. In addition, HH Angus puts strong emphasis on the key performance metrics that guide our clients’ business goals so that we can balance value and project delivery tailored to each client.

Energy Master Planning

Energy master planning provides the opportunity to consider current and future expected building uses and loads, up-front capital availability, and timelines to establish appropriate phasing of projects, level of planning and detail design, along with meaningful cost estimates and analysis. For example, on a project to expand a large pharmaceutical manufacturing campus, we performed a feasibility study considering year-round energy load profiles with specified hydronic temperatures and steam pressures conditions in order to maximize the value delivery of new invested infrastructure and lower carbon footprint objectives. We explored options involving a mix of steam to hot water heat exchangers versus a low temperature network with heat pump “boosters” at point of application, taking into account characteristics of the existing distribution network and equipment conditions while improving operational resiliency and redundancy. The final decision was to proceed with a system that would satisfy the existing needs of the buildings in the short term but be adaptable to lower temperatures in future as existing buildings are upgraded or replaced.

Case Study - Post Secondary Campus

For this project, we joined an industry partner to study the feasibility of a centralized retrofit district hydronic heating and cooling cogeneration plant. The study considered networking various existing decentralized building heating and cooling infrastructure. This approach provided significant energy savings through the higher efficiencies inherit in larger scale equipment, load diversification and less equipment to achieve redundancy requirements. The original design involved multiple magnetic bearing chillers and heating boilers, and gas-fueled cogeneration with placement of one central plant close to the various buildings. The project was partially driven by a concern for aging decentralized equipment that would be phased out within the next decade or so. Preliminary cost estimates identified limitations in the preliminary centralized design approach resulting from cost-inhibiting disruptions to an active campus for installation of distribution hydronic piping. As a result, our energy modeling and feasibility review focused on a phased strategic implementation to network a smaller cluster of campus buildings which required less up-front capital. This provided the benefits of the original iteration while supporting the owner’s longer term infrastructure upgrade plans. A peaking plant was separately constructed and successfully commissioned to support electrical demand.

End-of-life heating boilers replacement (left) with new high efficiency gas-fired condensing boilers serving various networked campus buildings; Fulton EDR+ units shown(right)

Retrofit Design

Facility owners approach design consultants looking for a solution to a current problem or a predicted problem. To provide a solution, several factors need to be considered, such as budget constraints and, often, limited (as-built) documentation available for existing facilities. Due to these constraints, some consultants may seek to use project solutions that worked in the past and limited information via site surveys, which may not take into consideration current operational conditions or other factors that were not considered during feasibility and modeling. This can lead to significant financial implications for the owner over the life of a plant. HH Angus recognizes that active early engagement with operational team members familiar with the facilities is often key to uncovering the optimal design solution approach.

On one project, we were retained for detailed design engineering work to scale up treated water storage to increase steam production for an urban district steam plant. This included requirements by the owner to minimize capital expense and limit plant space for the conversion by reusing existing infrastructure, including storage tanks and piping. We held discussions with experienced plant staff and reviewed multiple past retrofit projects that led to the current condition of the overall system. Our investigations brought to light atypical control sequences of past applications, operational limitations in sizing of piping that resulted in excessive energy consumption, and discrepancies in drawings and documents. Following a review with the control solutions consultant, our team was able to propose, develop and implement a flexible design arrangement in line with facilities engineering objectives, while minimizing disruption through detailed assessment and understanding of existing plant operations. These steps are critical in steering our efforts towards real capital savings and delivering value to our clients.


A growing trend toward low carbon energy production. This entails reducing the carbon footprint of a district energy plant and dependence on non-renewable energy sources such as coal, oil or natural gas for energy generation. Environmental regulatory bodies and design standards are increasingly stringent, but the push towards low carbon energy production is also driven by consumer demand, particularly on the west coast in North America. A good example is a decarbonization project at an existing fossil fuel gas burning steam plant where electric steam boilers will be used to offset production of the existing boilers. This involves an additional high voltage feeder arrangement with the local utility to support the infrastructure upgrade. A substantially reduced carbon footprint is expected throughout the life of this electric boiler plant that operates year-round. HH Angus is also increasingly incorporating the use of district energy steam to hot water energy transfer stations, heat pumps, geothermal, and low temperature ambient systems to support low carbon design initiatives. Look for a future white paper on heat pump applications.

Example: HH Angus piping design layout of district energy steam to hot water energy transfer stations

Another solution to meet the decarbonization goal is the introduction of thermal microgrid systems which utilize renewable energy sources, with thermal storage and heat recovery to satisfy low-temperature district heating requirements.  As renewable energy sources are used, the carbon footprint is significantly reduced in these systems;  for example, geothermal can be used as a primary energy source as it uses thermal energy from the ground, which is then distributed through the use of heat pumps. Thermal storage systems may also be installed with these systems to optimize the system and provide protection during load fluctuations.   


Beyond the conceptual, HH Angus generally seeks a collaborative approach to best utilize key areas of expertise between consultants, owners, and installation contractors during detailed design and construction. For example, market fluctuations in commodity pricing, such as steel—commonly observed post-pandemic—has impacted the construction industry’s supply chains, which poses significant risk to project stakeholders’ budgets and timelines. HH Angus has adapted workflows accordingly to better manage risk and unknown conditions, with cost reviews being referenced across various sources, including HH Angus’ active projects. The feasibility of early procurement of major equipment is reviewed with owners and suppliers to mitigate concerns relating to fluctuations in construction cost and timeline.

Building Information Modeling

Increasingly, the use of reality capture such as Matterport 3D scanner provides a much improved channel and engagement platform for communication of client needs and clarity in design scope, while enhancing and bridging gaps in technical subject matter otherwise difficult to describe during the project planning and development process.

Use of REVIT tools minimize the risk of drafting errors and improves engineering documentation quality through automation of equipment schedules, sections, and schematic drawings. Site scans further improve collaborative efforts between team members, dimensional accuracy during equipment layout, and clash avoidance, while facilitating client discussions and proposed solutions in detail.

Use of REVIT to illustrate conceptual preliminary central plant layout complete with boilers, absorption and centrifugal chillers, cooling towers, cogeneration, pumps, and economizers


For most building infrastructure, energy consumption contributes significantly to operational cost and risk. Energy needs represent a recurring, long-term expense for building owners who can benefit greatly from proactive management. An energy master plan can provide the road map needed to guide scalable and effective approaches to achieve deep energy savings, improve resilience, reduce carbon emissions, and increase  reliability.

Thoroughly reviewing and documenting a site’s energy systems, utility infrastructure, and future energy needs is the first step in creating an energy master plan. The next step is to combine this information and develop a forward-looking, holistic energy strategy focused on optimizing existing assets, hedging future energy risks, and further growth in sustainable options.

Justin Lau, B.A.Sc., P.Eng
Justin is a mechanical engineer in the Energy Division of HH Angus and Associates. He is involved with project development and detailed engineering design to help clients meet energy targets and carbon reduction objectives in numerous market sectors.

Sabari Manoharan, B.Eng., E.I.T.
Sabari is a mechanical engineering designer in HH Angus’ Energy Division. He is responsible for successful implementation of all aspects of design on low carbon projects under direction of senior technical staff.

Part One: Heat Pump Technology and Why We Need it

Building owners who are heating and cooling with fossil fuel energy sources are increasingly looking for solutions to reduce their buildings reliance on these fuels. This particularly applies to people-oriented buildings, such as commercial, institutional, and condo/multifamily residential buildings. Heat pump technology has come a long away in recent years; today, heat pumps are highly efficient, operate on electricity and can operate effectively in colder climates. While electricity is expensive, careful analysis reveals a heat pump solution can be more cost-effective than using natural gas. Heat pumps are also more efficient, have lower operating costs and will help owners looking to achieve net zero and significantly reduce their portfolio’s CO2 emissions. Heat pumps can also save on water use if using ground source heat pumps – more on this below. Climate change is one of the most important challenges of our time. Buildings account for 39% of energy-related CO2 emissions on an annual basis globally 1 and building operations (heating, cooling, lighting) account for 28% of emissions annually. Lowering carbon emissions from buildings is an important element in fighting climate change. In the near future, heating buildings with fossil fuels will increasingly cease to be an option as the world shifts to low carbon. We believe that heat pumps, compared to conventional heating and cooling systems, are more efficient and, when combined with low-carbon electricity sources, will play a critical role in transitioning building heating to low carbon.

Reality Check

Globally, electric heat pumps provide less than 5% of building heating today, yet they could supply more than 90% of space and water heating, with lower CO2 emissions than condensing gas boiler technology in electricity grids that have low emission electricity. In Canada, 80% of the energy used in residential housing is being used for space and water heating, and this produces approximately 98% of residential buildings’ GHG emissions. In a broader scope, more than half of all buildings in Canada are heated by fossil fuel energy sources5 and only 2.5% of buildings use heat pump technology.

Into the Future

Looking into the future of heat pumps in buildings, the United Nations (UN) developed seventeen Sustainable Development Goals (SDG) which were adopted by all UN member states in 2015. According to recent models, reaching these SDG would require heat pump sales to triple by the year 2030. In addition, heat pumps have to be the dominant technology for heating buildings around the globe. In a net zero scenario, heat pumps will have to replace all natural gas boiler sales that occurred over the last 20 years, see Figure 1. This prompted us to examine the future opportunities for heat pump technology in buildings.

What is a Heat Pump

A heat pump is a mechanical machine that utilizes a refrigerant to move heat energy from one place to another. This idea is based on the reversed Carnot cycle where a vapor compression refrigeration cycle uses input work to move heat from a relatively lower temperature energy source to a relatively higher temperature energy sink. The input work can come directly from a fossil fuel-based energy source, such as a natural gas-driven heat pump. Alternatively, the input work can come from an electrically-driven heat pump where the motor is driven by electricity from an electricity grid. This electricity may or may not be carbon free.

Electric heat pumps can recover low temperature energy from an energy source, elevate its temperature, and deliver it to an energy sink using a relatively small amount of electricity. In fact, the majority of the energy delivered by a heat pump used for heating comes from the low temperature energy source and not from electricity. Building owners or design engineers who evaluate heat pumps for building heating often rely on certain performance criteria to determine the benefit they can get from heat pump heating. Performance is also important when comparing heat pump heating to other heating methods, like using steam or hot water for heating, electric space heating, or direct furnace heating. The typical criteria used to evaluate heat pump efficiency is the Coefficient of Performance (COP) of the heat pump. The COP of a heat pump is the ratio between the heat delivered by the heat pump to the input work provided to the heat pump machine. In the case of electrically-driven heat pump, the input work is in the form of electricity. Therefore, the heat pump COP can be expressed as follows:

This COP (ratio) is typically greater than 1. This gives the impression that the heat pump has an efficiency higher than 100% which makes heat pump heating look attractive in terms of performance compared to other methods of heating. However, a COP higher than 1 may look significantly better than a natural gas hot water boiler efficiency but it is not necessarily the only indicator of a heat pump performance. Another way we look at a heat pump performance which is less mainstream is through comparing the ratio between the COP of a certain heat pump to the Carnot COP of the same heat pump under the same operating temperatures. The Carnot COP is the theoretical maximum COP according to the laws of thermodynamics. This ratio between a heat pump COP and the Carnot COP is always less than 1. This comparison provides us with a metric for the deviation of the COP of a certain heat pump machine we are evaluating from the theoretical maximum possible COP for this given machine. For reference, the Carnot COP is defined as:

Where all the temperatures noted above are in degrees Kelvin. This evaluation methodology highlights the importance of the design parameters of buildings such as temperature used for heating as well as environmental conditions that affect the heat source temperatures, such as outdoor air temperature or ground temperature. This helps engineers and building owners assess not only the performance of heat pump but also the feasibility of using heat pump heating in a building based on its location and building design parameters.

The good news is heat pump technology has been making consistent progress for the past decade. The performance of the current technology makes the use of heat pumps possible for a wide variety of building heating applications. However, the heating requirements for each building will determine the type of heat pump that is most suitable for the application.

Heat Pump Options

We can group heat pumps into two types based on the source of energy going into the machine: air source or water source. An air-source heat pump (ASHP) relies on air as a source of energy, which can be advantageous for climates that have mild air temperatures; however, in colder climates, the performance of air source heat pumps can deteriorate at lower outdoor air temperatures (typically below -20°C, if the energy source is outdoor air). Air source heat pumps can be installed virtually anywhere if physical space allows for the installation. This can be advantageous if there are no energy sources available to the building. However, the maximum heating capacities of an air source heat pump can be a limiting factor when using such technology for large scale applications, such as campus and district energy heating. Water source heat pumps (WSHP) use water as the energy source; this can be an advantage when abundant energy sources are available to the building, and in cold climates. If the energy source is reliable, water source heat pumps can provide building heating with a relatively smaller equipment footprint compared with air source heat pumps. Water energy sources can originate from ground, in the case of geo-exchange, or waste water heat, as well as process heat recovery in industrial applications or data centers. The caveat is that, sometimes, these energy sources may not be available to the building at all, or only available outside the building or at a distance far from the building, which can make such systems more expensive to construct.


So far, we have discussed the importance of heat pumps in combating climate change and improving overall building performance and outlined what the technology is and how it works. Stay tuned for Part 2 of our three-part discussion of heat pump technology examining the cost implications to owners and operators, as well as the considerations, opportunities and risks present for heat pump heating and how to navigate them. For more information about heat pump technology or to speak with one of our energy specialists, contact us at

Mike Hasaballa, M.A.Sc, P.Eng.
Mike is a lead engineer and project manager in HH Angus’ Industrial/Energy team. His work focuses on the design of efficient high-performance heating and cooling systems, as well as low carbon energy systems and energy master planning.

Francisco Contreras, M.A.Sc, P.Eng., LEED, AP BD+C, BEMP
Francisco is a manager and energy analyst in HH Angus’ Knowledge Management team. He is very experienced in high performance green building design, building simulations, and energy assessment.