The Smart Sustainable Resilient Infrastructure Association (SSRIA) is here to present its Green Building Technologies Network (GBTN) Spotlight Series. This series will be featuring a project team once every other month until March 2023. The aim is to get to know the projects and teams working in the GBTN and support further collaboration, communication, and knowledge sharing among our members.
Our guest this month is Landmark Homes, welcome!
Project Type: Multi-Unit Residential New Construction
Project Aim: Evaluating NZE/r MURB Design and impacts of large scale implementation on utility grid
Project Summary: Click here for the complete project summary
We are happy to have Landmark Homes with us for our Spotlight series, Edmonton’s leading master home builder with a focus on innovative design and construction. This month we are spotlighting the SSRIA GBTN test bed project Landmark Homes is building. The project is featuring innovation in developing and testing replicable solutions for MURBs to achieve NZE and/or NZEr performance. They also aim to develop a generic simulation tool to predict and analyze the aggregate energy profile of highly energy-efficient MURBS. Here’s what team lead Haitao Yu had to share about the project so far.
What has been the greatest challenge thus far in design and integration of passive design strategies on a MURB?
In order to achieve Net Zero Energy Ready (NZEr) goal, we need to significantly reduce the energy consumption through adopting high performance building envelopes and more efficient mechanical systems. However, in MURB’s, the effects of upgrading building enclosure are limited and not cost effective due to smaller wall to floor ratio. Meanwhile, in Alberta, electricity is 3-4 times more expensive per heat unit than natural gas. How to optimize the design to minimize both construction and operation costs, while achieving NZEr goal is a great challenge.
What considerations have been made to promote the replicability of future Passive MURBs, specifically in regards to design and the community consultation process?
With the tiered building code in the horizon, we are developing and demonstrating a viable solution that can help MURBs to achieve tier 4 energy requirements.
What advice do you have for others endeavouring to follow Landmarks footsteps; What is the biggest hurdle in convincing a developer to attempt a community sized PV panel distribution system on their projects?
Energy performance and sustainability will be a major, if not the most important, factor in future home purchase decision. It is important for rental project owners to have a long-term vision and the best way to maintain project value is to build the homes according to future building code standard. The biggest hurdle of community size PV system is the mismatching between investment and return. According to Alberta Micro-Gen Act, the solar generation must be used to offset the energy consumption of the same building. This means that the occupants will receive the benefits of the solar PV rather than the developer who invested in the solar PV. We need an mechanism for develop to share the benefits in order to make the community-level solar PV practically viable.
Can you explain in simple terms how the tool being created by the landmark group to predict and analyze a building(s) energy profile works?
The project research partner, the University of Alberta, will collect the actual energy profile data from the project and develop a neural network model to identify the key valuables impacting the building loads to the electrical grid. A forecast model will be developed to forecast the aggregative energy profile at MURB level. This model will be validated through overlaying the energy consumption and solar generation profiles developed using the historical data from other MURB projects and solar PV systems.
How much is the additional cost as estimated by Landmark to move a baseline home towards an NZE home?
The overall incremental costs of upgrading a MURB units from Landmark’s standard specification to NZE home standard is around $32,000, including $12,000 on energy conservation measures and $20,000 on a 8-kW roof-top solar PV system.
Load profiles seem to be a growing consideration in the designing and implementation of all electric powered homes. What changes need to occur on an infrastructural level to accommodate this fluctuation in peak demand and supply to make scaling up of electric homes feasible in Alberta?
Today the electricity service to a typical residential unit is 100 Amp. But for electrified NZE or NZEr homes, a 200 Amp service is needed to accommodate the peak loads in heating solar PV generation.
Can you explain more about how peak loads specifically impact NZE houses?
The size of electricity service is decided by the peak loads. As NZE home generally use electrically for space and hot water heating, its peak loads are much higher than conventional homes using nature gas as heating source. If multiple homes connected to the micro-grid are NZE homes, the infrastructure has to be upgraded to accommodate increased capacity, which will result significant investment.
The projects are using a dual-fuel combined space and hot water heating system. This technology uses an air source heat pump, tankless water heater, indoor air handler, and high velocity small duct distribution system. Can you elaborate on how this works, what energy supplies are used and how this method increases efficiencies and flattens the peak loads?
The dual-fuel combo system can heat the house using heat from both air source heat pump or tankless hot water heater. The thermostat is connected to a outdoor temperature sensor and depending on the outdoor temperature, the air handler switches between two heating sources to get the optimal heating results. Specifically, when outdoor temperature is higher than -10 degree C, the COP of air source heat pump is higher than 2, the home will be heated by the air source heat pump to reduce the energy consumption, When weather becomes colder, the system will use hot water from tankless water heater for space heating, reducing the energy costs and flattening the peak loads.
How has the analysis of both PV generation data from SolarMax and Energy consumption data from the Webber Greens Town home Community assisted in developing the design for the Maple West Townhouses being developed, what findings were there?
The Webber Greens town home community is a NZE ready rental project using the same floor layout and specifications. The energy consumption data collected from Webber Green will allow us to build a better energy profile forecast model using data set from two different locations, increasing model’s credibility.
You are in Milestone 2 of the project which involves the construction of mulitple townhouse MURBS including the installation of the PV. What type of Solar Panels are to be installed for the project and what were the results on PV analysis that influenced orientation and installation design?
The project will use the Longi 72-cell 455W Mono PV panels. The total installation capacity on Block 3 is 28.21 kW and annual generation will be 36,060 kWh according to the PV analysis. It is estimated the solar PV will offset 50% of the electricity consumption of the units. Another 8.2 kW system will be installed on the community event building to offset the electricity use of the common area.
What is the Monte Carlo approach used in simulating and analyzing the aggregative energy demand profile, how does it work?
Monte Carlo method is a computational algorithm that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be deterministic in principle. Based on the energy data collected from each MURB unit, we can develop a unitary energy profile model. However, this model will be a dynamic model with many randomly occurred events, such as washing or drying clothes or air source heat pump startup. Using Monte Carlo method, multiple energy profiles will be generated based on the probability of occurrence and overlaid to get the aggregative energy demand profile at building or community levels.
The energy consumption and GHG emissions reductions are much more appealing for the proposed NZEr homes being built could you walk us through the savings occurring from the code reference building to the new designs, where are the savings coming from?
Compared to the code reference home, the proposed NZEr building, without PV, will use 38% less energy, which is 27.4 GJ per town home unit annually. The saving is mainly due to high performance building envelop, air-source heat pump space heating, high efficiency HRV and tankless hot water heater. The roof top solar PV will further reduce its annual consumption by 11.2 GJ. Due to high carbon intensity of Alberta electricity, the GHG saving will mostly come from solar PV, about 3 tonnes per town home unit annually.
In your view, what will be the greatest reward or take-away from this project?
The project will demonstrate a viable NZEr MURB solution for Alberta housing industry and provide a ready-to-use tool to assess the impact of NZE and NZEr buildings to community micro-grid.