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I have a friend who's been talking up district thermal networks for months. This episode made it clear. Thanks. What I really like is bringing along the utilities as an ally rather than an opponent. Here in NYC, with Local Law 97 requiring emissions reductions, this can be a win-win. Lower cost plus lower emissions.

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I really hope this succeeds. For northern US climates and moderately dense neighborhoods it seems to have multiple advantages over individual air-source HPs. I believe the areas selected have a fair bit of multi-family housing in 3-plex walkups, etc. Some of these buildings probably have boiler heat. I'd be interested to hear what the systems are being selected to replace these. I understand actual construction starts this summer. There are many other permutations on this concept. Other HVAC geeks might be interested in these free webinars subsidized by NY state: https://www.ashrae.org/professional-development/chp-webinars/ashrae-nyserda-community-heat-pump-systems-webinar-series

In the EU, boilers in district heat systems are being replaced by heat pumps, many water-source, often using ammonia as the working fluid so the district heating HW can be supplied at 180F. That's covered in #13 in that series.

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This is already such a hopeful series, I love it. What a cool idea.

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David it is good you are tuning in to low carbon district energy. There are many, many existing low carbon DE projects around the world using a wide range of energy sources. Europe, in particular, has much greater market penetration for district heating than North America and most DE utilities in Europe are working on transitioning their systems to lower carbon resources. This is an interesting initiative and I look forward to listening.

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Great podcast. Thank you.

I was listening for mention of other thermal resources and their cost/value to the new thermal grid: water heaters, refrigerators... and of course, pools and hot tubs. And for rural and semi-rural landowners, unused water (and oil and gas) wells may become new thermal assets. Municipal water tanks and ponds are designed and managed to avoid freezing; now they can also become thermal assets.

Another interesting area for fresh thought is efficiency. As part of the Transition, we still need to strongly incentivize improvement in building efficiency. Consumer cost is going to become dependent on insulation if the cost is based on consumption. (BTW: COP is proportional to the efficiency of the machine that moves the mass that contains the heat and inversely proportional to the "distance" (temperature) you move it. The less different the two temperatures are of the source and sink, the higher the COP.)

Still another resource is solar thermal. Where a bit more energy is needed, solar thermal can be installed near the need. Solar thermal could finally "arrive" in America.

Thermal resources need to become the center of new thinking for many needs. For example, dehumidification.

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Thank you for this inspiring discussion.

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@David, Check this out: Smith College, in Northampton, MA, is converting their entire campus-wide heating and cooling system to geothermal heat pumps! That's 90% of their current carbon footprint. Would make a great use-case podcast: https://www.smith.edu/news/modeling-carbon-neutrality

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Really enjoyed the listen, but I felt that the cost implications on the customer's side of this weren't fully expressed. The customer still needs a way to transfer that thermal energy in the water to the air of their forced air heating/cooling system. It’s certainly doable, but a higher capital expense than most customers are usually willing to swallow, and it’d be hard for the utility to own that piece. Not to mention the finances become a complete train wreck if they’re using a radiator heating system. Don’t get me wrong, I’m still all for this, but the retrofitting costs are not to be taken lightly. It is not simply “plug and play.”

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This idea would make heat pumps more efficient; but rather than go to all the cost and labor to get a higher COP, we could just install more cheaply - more solar modules to make up for the COP efficiency gains from ground- based heat pumps.

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Can't listen yet, but this strikes me as counterproductive to the push to electrify everything. For city/communal/apartment systems I could see it be useful at scale. For more suburban settings, seems like a water main break problem that now also means you have no heat, since invariably they'd be mostly co-located in the infrastructure routing.

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