kenmore heat exchange system

Last night, at the suggestion of Megan from the MCA’s registration department, I went along to a talk at the Maritime Museum. The guest speaker was Rebekah Wood, an architect and conservator from the USA, who introduced Kenmore, a historic-house-and-museum in Virginia where she works.

Kenmore makes for an interesting case study in “eco-conservation”. What they’ve done there is of great relevance to registration and conservation professionals – and it connects almost uncannily well to the discussions I was having the other day with Claire, Megan and Melanie at the MCA: how to balance the need to protect yer cultural heritage items, against the increasing pressure to tread more lightly on this planet of ours.

In 2003 the Kenmore house installed a Geothermal HVAC System.

HVAC stands for “Humidity Ventilation Air-Conditioning”. Geothermal is just a general term that means “of or relating to the heat in the interior of the earth“.

As far as I understand it (and I hope someone will correct this simplistic and possibly erroneous caricature I’m painting here), the underlying principle is this: underneath the earth’s surface, the temperature stays relatively stable, whereas up here on top, as we know, we suffer (and enjoy) great temperature and humidity variations.

The geothermal system works on the idea that in the summer, the temperature aboveground is higher, and in the winter, the temperature aboveground is lower than that of the earth below. So, all you need to do is a kind of “heat swap” between the two zones, and you have a fairly low-energy heating and cooling system.

Here’s a diagram that looks like it could have been drawn for Kenmore itself (but wasn’t):

heat pump diagram

There’s more good info where that pic comes from.

A bunch of pipes snake down into the earth near the house, and through these pipes are circulated a refrigerant gas which does the work of exchanging hot and cold. So it’s kind of like a fridge with all those wires and pipes at the back of it, except the pipes are buried deep beneath the surface of the earth (in Kenmore’s case, 170 feet deep)… and the fridge can make things warmer as well as colder…

Since installing the new system, Rebekah says that Kenmore has saved eight and a half grand a year in energy bills. However – (and this was the bit that came under scrutiny from some of the museum professionals in the audience) – it cost a million bucks to install in the first place. I could see the cogs turning over in their heads. If a conventional HVAC system would cost about $200,000, that means that this nifty eco-geo-version represents about $800,000 extra cost for the initial install. That means it’s gonna take 100 years (at current electricity prices) to pay it back. The boffins in the crowd decided that, from an economic perspective, it was thus “not worth it”.

However, there are obviously other issues at play. For instance, while paying your power bills is pretty banal, overhauling a big system like this is a sexy idea. It makes Kenmore into a leader in the field, and can attract big grants to help get it done.

In other words, the money invested has other kinds of dividends – not just savings on energy bills. It also means that Kenmore gets kudos for being “a model museum”, a kind of living experiment, a case study for others to adapt and copy, the avant-garde of the new world order, and all that.

energy saved vs energy consumed

While there was a lot of talk about the financial costs and savings of the geothermal system, Rebekah didn’t mention the overall budget in terms of greenhouse gas emissions. So, doffing my Auditor cap, I ponied up with this question:

“With the geothermal system, what is the amount of energy savings per year, compared to the amount of energy that was consumed in the first place, installing the new system? In other words: how long will it be before Kenmore breaks-even in terms of carbon emissions?”

Looking apologetic, Rebekah said that this was a sum that hasn’t yet been added up.

I should note, however, that overall energy savings are not the only factor at play. Rebekah has been a great campaigner for challenging the paradigm of 55% humidity / 20 degrees celsius as the strict parameters for taking care of precious objects. In her postgraduate thesis, called (something like) “Busting the Myth”, she demonstrated that artworks and buildings could withstand a much greater temperature and humidity range, as long as the transition happened gradually.

What this means is that, regardless of the type of heating and cooling system in place, you can actually get away with spending a lot less on temperature and humidity control, without objects cracking, warping or melting on you. It’s harder, I imagine, is to convince institutions and insurance companies to trust in this idea… I’ll be contacting Rebekah soon – she said she’s happy to pass along her thesis, so hopefully more of her myth-busting ideas can come to light…

There’s way more to say about Rebekah’s talk – stuff about condensation, and about the impact of heating/cooling systems on the fabric of heritage buildings themselves. But I think my fingers are about to drop off, so I’ll leave my auditing at that, for today…

6 Responses to “A Model Museum?”
  1. Ian Milliss says:

    Having had some involvement in heritage and house museum issues I find this all a bit problematic. There are two separate but conflicting issues. One the one hand , yes a geothermal systems can be an improvement on a conventional systems. On the other hand it begs the question of whether there should be any climate control system at all superimposed on a historic building.

    Probably the most important reason for the maintenance of heritage buildings is to demonstrate the different ways people have lived in the past and for that reason the restoration and maintenance of the original technology of a house is crucial. Retrofitting a historic building with contemporary climate control technology is a form of vandallism, albeit a very common form.

    It is becoming a major issue because many of the solutions to sustainability already exist in the past. The design issues around sustainable buildings in all sorts of climates have been solved hundreds, even thousands of years ago and house museums that demonstrate these sustainable technologies are now more important than buildings preserved merely for aesthetic, historic or more commonly, ideological reasons. The whole house museum model has been in decline over the last decade, even Colonial Williamsburg has been in trouble, and organisations throughout the world have been searching for ways to rescue that model with integration into the local community as a type of community centre or as a teaching centre for building technologies being favoured alternatives.

    Above all the issue is not just the illustration of sustainability in the past but more subtly, and possibly even more importantly, house museums have a progressive ideological role because they can demonstrate that people led fulfilling lives in totally different circumstances. By demonstrating that possibility they can also help remove the fear of a totally different future that seems to paralyse so much political action and delay adaptation.

    Interesting book on sustainability and heritage issues is “The Original Green – Unlocking the Mystery of True Sustainability” by Stephen A Mouzon (Guild Foundation Press, Miami). It’s a specialist niche that deserves a lot more publishing in the future.

  2. Lucas says:

    Ian, of course!

    My apologies – this is a classic situation that occurs from time to time in my blogging life, where the blindspots in my writing are immediately brought to light in the comments… So be it!

    So! Consulting my notes from last night, I find that Rebekah, who gave the talk on Kenmore, is indeed a strong advocate of the ‘doing a bit less’ philosophy.

    She pointed out that old buildings like Kenmore had indeed survived just fine, before the advent of sophisticated air circulation systems. Being made of thick stone, they have a high thermal mass, and so have a tendency to maintain quite stable climactic conditions within themselves.

    Secondly, she pointed out that the HVAC systems which are often installed in historic buildings can, as you say, enact a kind of vandalism upon them, because they have to be bolted, bored through, and ground away in order to make way for the new technological infrastructure.

    (Incidentally, at Kenmore, the geothermal systems were apparently much less intrusive in this respect, as they were able to be ducted through the existing fireplaces and so on, with the major mechanics located underground, outside of the main building itself).

    Third (and this is probably the worst bit, and Rebekah’s particular bugbear) changing the climate within a building, making it drastically different from the outside, can cause condensation to form. This hastens the decay process of the building envelope itself (not to mention creating health problems for those that work within it, from mould spores and such). — A case of a well-intentioned preservation intervention tactic which actually exacerbates the very problem it was introduced to solve! (Ya gotta love humans, eh?)

    She cited a place called Drayton Hall – which apparently follows the do-nothing approach. In this way, the ‘heritage’ of the building extends to our sensual experience of it (cold, hot, humid, whatever) rather than being subsumed by our demand for modern standards of comfort.

    In fact, in closing, she mentioned that one of the biggest hurdles to such minimalist heritage philosophies is that you still have to get people to work in these buildings, and people can be pretty resistant to an uncomfy workplace.

    Ian, I like the idea which you bring of the ‘house museum as active community centre’. In a way, this honours the building by giving it a useful contemporary job to perform, rather than putting it out to pasture and getting all precious about keeping it the way it always was (and destroying it in the process).

  3. Lucas says:

    Oh, and thanks for the book tip – I’m collecting such tips as a reading list I suppose, and I’ve linked to it (via the behemoth online book selling company) in the right hand column…

  4. Lucas says:

    More great links as sent to me by MCA Conservator Melanie:

    Sarah Brophy’s blog “SUSTAINABLE MUSEUMS”:
    http://sustainablemuseums.blogspot.com/
    …in which she tackles the practices of museums in the era of climate change.

    From Sarah’s blog (actually her Twitter) I found this interesting link too:

    http://www.sustainablepractice.org/2010/06/16/eco-bling-why-the-arts-sector-needs-to-lead-on-climate-action/

    Here’s a quote from that essay by Lucy Gibson:

    How should the artworld be responding to the issues of sustainability and the environment? Dialogue editor Lucy Gibson looks at why the arts should be leading the way on climate action, rather than looking to corporations and science for moral leadership. But in a sector made up of many individuals and small organisations, alongside enormous institutions, why and how can change really be affected?

    -and-

    The International Institute for Conservation of Historic and Artistic Works’ Dialogues page:

    http://www.iiconservation.org/dialogues/

    where you can find amongst heaps of other things, this interesting and relevant public discussion:

    For over four decades the environmental guidelines for museums and archives have been defined within narrow parameters. While many factors influenced what became standards, the narrowest range of conditions and the greatest insistence on them, came when energy was relatively cheap, global climate considerations were not yet mainstream discussions, and the technology of HVAC systems was focused more on control than efficiency.

    Given the looming energy crisis, the global economic downturn, and the rising awareness of green technology equating to good stewardship of our natural resources, responsible and efficient environmental control has become essential.

  5. Lucas says:

    UPDATE –

    After writing all this, I had a small chat with Sarah Brophy, whose blogs I referred to in the comment above.

    You can see my discussion with Sarah over at her blog.

    Here’s to new friends born of complex problems!

  6. Dear Lucas,

    I believe you’ve “hit the nail on the head” with your commentary on my talk and the use (or misuse, as the case may be) of environmental control systems in historic museums.

    Even better, the responses that the commentary is drawing resonate perfectly with my core message in that we do not need to go all out in heating and air conditioning historic museum structures…not even for the sake of the collections and (dare I say it?) for the sake of perceived “human comfort” levels.

    Rebekah K. Wood

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