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):
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.
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…