Building Energy Efficiency Assessment of Renewable and Cogeneration Energy Efficiency Technologies for the Canadian High Arctic

Arctic communities, challenged by the harsh climate and a lack of local energy resources, are often confronted with finding more sustainable solutions for power and energy. Due to their isolated nature, reductions in energy or fuel use can have important implications for operating costs, security, and energy independence. While high performance buildings have received significant attention in more populated areas, there has been less work done on the opportunities and challenges for these buildings in the Canadian High Arctic. Providing cost-effective logistical support for researchers in the high Arctic, the Polar Continental Shelf Program has operated a field logistics support hub in Resolute, Nunavut since 1958. With increased demand for logistical support and training over the past decade, the Resolute facility has undergone two significant recent expansions. The facility now contains over 7,400 metres squares of living and working space including the Martin Bergmann Complex (provides accommodations for over 237 people), the Operations Centre (warehouse storage, mechanical shops and offices) and the Dr. Roy “Fritz†Koerner Laboratory. With the increased operational requirements, the facility has seen a significant increase in energy use, greenhouse gas emissions and ultimately utility costs. As such, there is a strong desire to reduce energy use and provide for more sustainable facility operations. As the Polar Continental Shelf Program Resolute facility is fairly energy efficient (1.0 GJ/m²) and well maintained, to achieve deep energy savings it is necessary to examine the impact of more innovative strategies, including the integration of cogeneration and heat pump systems. This paper will present an analysis of different energy efficient technologies and strategies for high performance buildings in the Canadian High Arctic. Thus, a comprehensive energy efficiency analysis is performed using the TRNSYS energy simulation tool. First, detailed energy models of the current facilities are developed and calibrated using monitored data. These energy models then form the base for an analysis of innovative energy efficiency strategies including the integration of onsite cogeneration, cold climate heat pumps, and solar integrated technologies. Each strategy is then examined within a techno-economic framework to determine potential utility cost savings, GHG reductions, and simple payback periods. These results provide an important base for the discussion of future high performance buildings in the Canadian High Arctic

Techno-Economic Analysis of Heat Pump and Cogeneration Systems for a High Performance Midrise Apartment in the Canadian Climate

With increased awareness on the importance and benefit of energy efficiency, building owners and designers are frequently confronted with the challenge of which mechanical system is most suitable to meet the building’s energy target needs. The decision making process is often aided through the use of building simulation tools; however this type of analysis is often considered costly and time consuming in particular when various mechanical systems need to be assessed. With Natural Resources Canada’s priorities on promoting the sustainability and economic development of Canada’s natural resources, this paper presents an analysis conducted on several standard and innovative mechanical systems to aid decision makers in the early building design stages to select a suitable system. The paper further illustrates the benefits of each system type often not known or misunderstood. Using TRNSYS, five system types are evaluated in a typical newly constructed high performance mid-rise apartment in two Canadian regions: Calgary and Montreal. The five systems selected for comparison include (1) a conventional mid-rise apartment heating and cooling system, (2) boiler/cooling tower water source heat pumps, (3) ground source heat pumps, (4) a cogeneration unit sized to meet the heating load of the building and (5) a cogeneration plus electric driven heat pump system. Heat pumps were selected for the benefit in upgrading and utilizing renewable energy sources and cogeneration for the conversion of natural gas to electricity. The analysis includes a 20 year life cycle cost including a sensitivity analysis on forecasted utility rates

Annual Performance Of A Solar Assisted Heat Pump Using Ice Slurry As A Latent Storage Material

Solar assisted heat pump systems offer an attractive method of reducing the energy used for space heating and cooling, while efficiently using low temperature renewable energy from the sun to reduce the degradation of heat pump performance at low ambient temperatures. However, the majority of these systems use sensible storage to bridge the gap between thermal supply and demand, with the maximum storage capacity limited by physical constraints within the building. Latent storage has the potential to significantly reduce the required tank volumes in these types of systems. Previous work has demonstrated the benefit in heating mode of combining a solar heat pump system with ice based latent thermal storage, with this type of system achieving an up to 86% reduction in space heating energy use compared to a conventional system. The objective of this paper is to expand upon these findings and examine annual system performance in various Canadian climate regions through the evaluation of an innovative new operational mode providing space cooling to the building. The proposed system has distinct heating and cooling modes of operation. In heating mode, energy obtained from the solar collectors is stored in the ice tank. Thermal energy is then extracted from the ice tank using a heat pump, and delivered to a warm water tank acting as the distribution point for heating and DHW loops. An innovative new cooling mode is also presented, where the heat pump is used to build a cold storage reservoir for cooling purposes during the summer months. Excess thermal energy is then dissipated at night using radiative cooling (via solar collectors) or an air cooled condenser. Anticipated system benefits include increased energy storage densities, improved solar collector efficiencies, and potential utility cost savings by operating the heat pump during off-peak hours. To perform the analysis a computer model of the proposed system is developed using the TRNSYS energy simulation program, and integrated into high performance homes in three Canadian regions (Montreal, Toronto, Vancouver). Annual simulation results are presented and compared with typical base case designs in order to assess the viability and potential energy savings. A sensitivity analysis on several system variables is then presented in order to identify key design parameters for improved energy performance

The Potential of Liquid-Based BIPV/T Systems and Ice Storage for High Performance Housing in Canada

ASHRAE Vision 2020 has defined market viable net-zero energy buildings as a key objective for new construction in North America. Designing for this target requires the effective integration of renewable energy systems into the building. However, many buildings have limited roof and façade areas in which to integrate these systems, making it difficult to achieve a net zero energy design. Building Integrated Photovoltaic and Thermal (BIPV/T) offers a potential solution to this issue by converting the building envelope into an active producer of both thermal and electrical energy. Commonly, BIPV/T systems in North America have used air as a working fluid. While this offers easy integration with the building ventilation system, air also has a lower thermal capacitance, reducing thermal energy extracted from a BIPV/T collector. Liquid based systems offer working fluids with higher thermal capacitance, along with the ability to easily integrate with existing thermal storage systems. However, these systems often circulate warm water in order to directly meet heating and hot water loads, resulting in reduced thermal and electrical efficiencies and less durable BIPV/T modules. Circulating cooler water to the collectors can significantly improve both the thermal and electrical efficiencies of liquid based BIPV/T systems. However, the low grade thermal energy collected must then be upgraded for use within the building. This paper examines the potential of using liquid based BIPV/T systems with cool storage and heat pump technologies to meet the thermal demands of a high performance Canadian home. An innovative liquid based BIPV/T system is proposed in which the collector array is connected to a cool storage tank, while a heat pump is used to upgrade and deliver thermal energy to the building. Both sensible and ice-based latent storage options are examined as cool storage possibilities. To perform the analysis, TRNSYS is used to simulate the proposed system integrated into a high performance home in Montreal, Canada. Annual simulation results are presented and compared with typical base case designs. A more detailed temporal analysis of electrical loads is also performed in order to examine the impact of the proposed system on the electricity grid.

Economic optimization and parametric analysis of large hybrid ground source heat pump systems: A case study

Hybrid ground source heat pump systems offer a solution to reduce initial costs and make systems more economically viable. Their design is however complex and their financial profitability difficult to establish. The design of hybrid system is usually determined by following rough rules and is neither mathematically rigorous nor optimized. In this paper, a methodology recently introduced by the same authors for economic optimization of hybrid ground source heat pump systems is used to carry out a parametric analysis and assess the impact of uncertainty on the optimal design solution. The results show that all the parameters have significant impact on the optimization, and the ground heat exchanger construction costs and ground source heat pump COP had the most impact on the net present value. However trends are difficult to observe because if the non-linear nature of the problem, and thus there is a need for more robust optimization of hybrid GSHP systems under uncertainty

Simulation based assessment on representativeness of a new performance rating procedure for cold climate air source heat pumps

Cold climate air-to-air heat pumps (CCHP) offer a strong potential for energy use reductions in Canadian homes. Proper selection of the unit is critical in order to take advantage of the improved efficiency and increased heat capacity at low ambient temperatures and ability to modulate to meet a wide range of heating loads. A new performance rating procedure (CSA EXP07) was developed to better represent the seasonal energy efficiency of CCHP systems versus current test procedures that do not always accurately characterize the response to dynamic loads in a colder climate zones, thus resulting in inaccurate equipment rating. To validate the representativeness of the new performance rating procedure and quantify the potential over-or underestimation of energy savings using current performance rating procedures, a CCHP data-driven model is developed and simulated in a code-compliant single-detached Canadian home for different climate regions: Marine, Cold-Humid, Cold-Dry, Very-Cold and Subarctic. These energy models then serve as the basis for comparing the seasonal heating coefficient of performance of a CCHP system, which can be compared to the current and newly proposed performance rating procedure

Studying the impact factors influencing variable-capacity heat pump energy performance through simulation

Cold-climate variable-capacity air-to-air heat pumps (VCHPs) have the potential to significantly reduce energy use in the Canadian residential sector. However, optimizing their integration in the Canadian climate can be a challenge, with efficiency and operating behaviour heavily dependent on ambient conditions, building thermal loads, modulating capability and the units’ individual performance characteristics. Better understanding how these factors influence energy performance can lead to improved system selection, and ensure that high efficiency space heating systems contribute towards meeting Canada’s emission reduction targets. This study outlines three major factors – individual performance characteristics (cold climate capacity, part load performance), modulation ratio and sizing – related to VCHP selection, and examines their relative impact on annual energy use and operating behaviour using a simulation-based approach