The Next Generation of Mixed-Use Developments Will Include Industrial Space. **Energy Analysis **(Part 3 of 3)

As we continue our investigation of adding a 4th or 5th use to a Mixed-Use Developments we need to ensure that we are creating a competitive advantage over what the Industrial Sector already sees in their existing single or two storey facilities.

There are two clear challenges that the existing industrial building archetype is a large amount of exterior envelope in proportion to the Gross Floor Area and the opportunity to reduce the Peak Energy Demand and the resulting costs. But first, we are going to break down the electrical energy performance and costs.

What Would a 4-User Mixed-Use Developments Peak Electricity

One of the biggest opportunities to reduce cost is to address the Peak Electrical Demand. This typically accounts for 5 - 10% of a large building's electrical bill. Once we overlay all of these programmatic uses (assuming all users have the same peak demand load of 5000 kW) over a 24-hour cycle we can clearly see that there is a Peak Electrical Demand of 15,250 kW in the 1 PM hour.

What would happen if we adjusted the industrial time of operations so it does not contribute the other 3 users Peak Electrical Demand times?

This has a 27% reduction on the total Peak Electrical Demand. This, in turn, would reduce the electrical bills for everyone, or could be used to significantly reduce the electrical bill on the industrial user.

How to assign Peak Electrical Demand Costs to each user?

Now that we know that there is the potential for saving some costs, let's look at four different scenarios where we can assign the costs and savings:

Scenario 1 - Baseline: This is the comparison that if each user were to be in their own building and separate Peak Electrical Demand. Basically, not in a mixed-use development.

Scenario 2 - Average Shared Costs without Shifting Industrial Operations: This is the average of what the Peak Electrical Demand costs are shared equally between all four users regardless of each user's Peak Electrical Demand contribution.

Scenario 3 - Average Shared Costs with Shifting Industrial Operations: This is the average of what the Peak Electrical Demand costs are shared equally between all four users regardless of each user's Peak Electrical Demand contribution.

Scenario 4 - Proportional Costs with Shifting Industrial Operations: This is the proportional costs of what the Peak Electrical Demand costs as it relates to each user's Peak Electrical Demand percentage contribution.

The most interesting thing in Scenario 4, is that the Industrial Peak Demand Cost is almost $22,000 lower than if they were in a separate facility, that amounts to a saving of $262,668 per year. This means that the owner can charge a higher rent which would be offset by their reduced energy costs.

What about the exterior surface areas which would be reduced for the Industrial user?

How does a typical industrial building breakdown as a percentage of roof & exterior cladding vs. the gross floor area?

Using an Amazon Fulfillment Centre as an example we see that roof area as a percentage of Gross Floor Area is 89.6% and the exterior cladding as a percentage of Gross Floor Area is 14.6%.

This means that at the time of construction there are costs associated with these surfaces as well as an impact on the construction timeline. This would also increase the life-cycle costs associated with maintenance and replacement over the 50-year life of the building.

Another important consideration is the energy-related costs associated with heat gain and loss as a result of an exterior envelope which is equal to 104.2% as a percentage of the Gross Floor Area. This high ratio means that the energy costs per square foot will be higher than a facility which can reduce this relative percentage, such as a mixed-use development.

In my Design Scenario, there is no roof area associated with the industrial (Green in the image to the right) portion of the building as it is capped off with a sky lobby & conference centre. As for the cladding areas, it achieves only 5.4% of cladding as a percentage of Gross Floor Area. This is due to the office towers abutting the industrial portion of the building on all four sides.

This design achieves a reduction of exterior envelope reduction of 98.8% as it relates to the Amazon Fulfillment Centre. This reduction would translate to an energy cost savings.

*It is important to note that there would be costs associated with fire separation from the industrial area and the other uses on the project, but from a cost perspective, this should be cheaper than an exterior cladding system as well as faster to construct.

Other Opportunities

Surplus Heat Energy

Another one of the opportunities is taking the surplus heat energy from the industrial spaces and using it to preheat water and fresh outdoor air for the other users. This is just one other example, but, it would need proper energy modelling to ascertain the actual cost savings or value that could then be given to the Industrial Users rent.

Structural Stability

Can you build taller if you have a larger footprint and a higher level of stability higher up a tower? The answer is YES. This means that this might be a long sought after programmatic use for Mega-Skyscrapers, they need a larger footprint at the lower part of the tower in order to allow the upper portion of the tower to achieve record heights and this additional programming may be the solution.

Construction Staging

The construction of a Mega-Skyscraper, like the one you have seen, will require mid-level step backs for construction logistic management as well as to allow early occupancy of the lower third of the tower years before the entire tower is complete. This will assist in the financial proforma of a project of this scale.

Flexibility

Within this design approach, there is the flexibility to reduce the height or move the residential and office spaces around depending on the profitability and demand within the market.

Summary

That was a lot to take in, I know, it took me 2 weeks to pull all this together.

But, what do you think? Are we in need or ready for this next generation of mixed-use developments?

I've only looked at a couple of the key items which would help a development like this move forward, but there are a lot of challenges as well, considering the size and complexity of the project there will be a general premium to the construction. But if there was a lack of land or shifting demand for light industrial spaces near the downtown (like the increasing automation in the industrial field), then this would be a perfectly viable option and approach.

Lastly, a project of this nature would be a game changer and if it is viable it would be poised to redefine mixed-use developments in ways that have never been seen.

Have any thoughts? Share them below, and as always please share this article to help others learn. And don't forget to check out my other articles.

Blog post by: Jorden Lefler, Senior Sustainability Manager