Thursday, March 31, 2011

Look in the sky - it's a bird! it's a plane! it's supercooled air!

On March 11th Landmark Facilities Group, “the guys” for environmental control systems (as described by the Director), came to poke around the museum. “The guys” have done work at Lyndhurst, Martin Van Buren National Historic Site, Darwin Martin House and the Isabella Stewart Gardner Museum. Whether they are “the guys” or not, one thing is clear – they sure do get around. I sat down in the Director’s office with a pen and a piece of paper (scrounged from the top of the Business Manager’s desk) to take notes about the March 11th visit. I noticed as I asked my first question that the Director was instantly absorbed by something on her computer screen. I snuck a quick glance over her shoulder and realized that the only thing she could possibly be looking at on her computer was her screen saver bouncing around the monitor. Surely that wasn’t such a compelling thing to watch. Then the thought occurred to me…she was avoiding me. Or more specifically, she was avoiding my request for a summary of “the guys” visit. When I pressed her again with my question, she looked away from her computer and stared blankly at me, as if she had not only forgotten my question but also who I was. But I wasn’t falling for that trick…again.

Squirming uncomfortably in her comfortable chair as I stared her down, she finally confessed the truth. She couldn’t really remember what “the guys” told her on the 11th. She stressed that their visit had almost entirely excluded her presence. They were looking around and taking notes. They recapped their findings to her at the end of the visit but it was “all a haze” for the Director. The bitter taste of disappointment filled my mouth. What was I going to write about this week? Hanging my head and slumping my shoulders, I started to leave the Director’s office in search of #3 wondering if there was anything more exciting I could get out of him regarding the window restoration. (FYI – #3 and his companion, #4, have almost all of the first floor restored windows reinstalled and were hoping to start on the second floor windows this week.) The Director (most reluctantly I might add) called out my name to stop me from exiting her office. Perhaps her pity for the Communications Coordinator whose blog posting plans she had so callously crushed under her heel moments before motivated the next sentence out of her mouth. More likely she knew she could not postpone the inevitable – that I would return to badger her for information at some unknown future date. Whatever her reasons (and honestly, who can understand the mind of a Buffalo Sabres fan?), she said, “There was a phone call.”

Like a Labrador puppy whose feet are too big for its body, I stumbled over myself in my eagerness and excitement to hear about the phone call. A call came in on March 18th from “the guys” during which they explained their drawings and recommendations for Historic Cherry Hill’s environmental control plans.

Hold on to your hat, this might get a little bumpy. First of all they proposed two zones within the house. The first would be the Collections Area Zone. The second would be the Human Comfort Zone. Two separate air handler units would be installed in separate locations in the house to maintain the appropriate environmental conditions for these two different zones. The air handler unit for the Collections Area zone would be installed in what is now our main furnace room. The main furnace room is tucked right next to the bottom of the basement steps. Opening the door one is immediately faced with an enormous furnace - really, it’s something I imagine the first computer to look like.
This enormous furnace takes up almost the entire space, except for a little nook around the corner from the door where some collection is being housed (much to the surprise of the Curator). The enormous furnace is probably collection. It may date back to the Rankin era. This enormous furnace/potential collection piece would ultimately be removed and (gulp) stored at the collections building. In its place a new heating unit would be installed. “The guys” believe that existing ducts and registers could be used to control the spaces on the 1st and 2nd floors for the Collections Area Zone.
The Furnace Room - Where Bad Communications Coordinators are sent never to be heard from again.  Around the corner to the right is the hidden surprise full of, among other things, collection pieces.
So what do these needy objects in the collection require in the way of temperature? With this proposed system, the temperature could potentially get as high as 80˚F in the summer. Apparently the warmer the temperature is, the less humidity in the air. It’s an inverse relationship thing– the hotter the air, the drier the air. In the winter time the temperature could go as low as possible. Wait. Stop. Stop trying to understand what you just read. I really wanted to explain this part in my own words but what I just wrote doesn’t make any sense. I will instead share with you the Curator’s superior knowledge and understanding of relative humidity and a delicious ice cold glass of Coca-Cola on a hot summer day:

Everyone will find this confusing bc everyone knows that in the summer, when it’s HOT, it’s also more humid. So, what’s with this inverse relationship???

Here’s the thing: RH refers to how much moisture is in the air compared to how much moisture that air can hold. (That’s why it’s “relative” humidity.) Warmer air can hold more moisture than cooler air. That’s why in the summer when moist air hits your glass of cold soda, the air drops its moisture as it suddenly cools—the air around your glass has cooled, so it just can’t hold as much moisture anymore—so you get condensation on your glass.

Now…in winter, let’s say that humidity outside is 50%. You bring that 50% humidity air inside, and you heat it up. You now have warmer air that could hold more moisture than before, but you haven’t added any moisture to the air. So your relative humidity has dropped. In a sense, the warmer air wants to hold more moisture, and the people and things in the room respond by giving up their own moisture. People get itchy skin and furniture shrinks and cracks. By letting the collections areas of the house go cold in the winter—by not heating up the air too much—we will keep the RH a bit higher. So instead of 15% RH, hopefully we can keep it in the 30s. And we will also save money.

Now doesn’t everyone feel better, and just a little bit smarter? (Honestly, I don’t feel smarter. I just feel thankful that the Curator exists.)

The Human Comfort Zone is a different matter entirely. This zone would encompass the Director’s Office and the bathroom on the first floor and the entire basement.

The Director's Office would be located in the "Human Zone" though it might not look like there is room for a human to sit behind that desk.
"The guys” propose placing an air handler unit for this zone (and a gas-fired boiler which will provide hot water to both zones of the house) in the ladder room which is a storage space built into the basement level of the house but only accessible from the outside. A circulating pump will distribute hot water (from the boiler) to heating coils in each air handler unit.

This the door to the ladder room.  I can't show you the inside of the ladder room because, well...apparently...I lost the keys to it. 

The use of this space for the heating equipment would have some minor impact on the appearance of the exterior. A small vent, (6” in diameter) would be placed on the ladder room walls which would be visible from the outside, especially when releasing steam. And while we are on the subject of exterior impact, “the guys” also proposed placing the three condensing units (which would be located outside) underneath the front porch of the house to minimize their visibility. These proposed external elements would have to be approved by the New York State Office of Parks, Recreation and Historic Preservation as Historic Cherry Hill is on the National Register of Historic Places and we are receiving public funds for the project.

I needed further definition of human comfort (considering the subjective nature of the concept) and asked the Director to oblige me by explaining what it meant for our proposed HVAC system. “Nice & toasty,” she answered. Not as illuminating an answer as I had hoped. One person’s nice and toasty is another person’s ice box. “Between 68˚ and 72˚ F,” was the further clarification from the Director and the Curator. Hold the phone people! Between 68˚and 72˚? My first thought was ‘Will Child Protective Services take my children away?’ because at my house we keep the thermometer at the apparently subarctic temperature range of 63˚ to 65˚. 68˚ to 72˚? My next thought was ‘Would the Director and the rest of the staff notice if I moved my family into the museum during the winter months?’

The Bathroom - part of the "Human Zone."  I'm confident that I could fit at least three of my kids in that bathtub and there is probably enough room on the floor for the rest of us.

To create this Human Comfort Zone throughout the entire basement, HVAC people would have to cut a few holes in the walls to run ducts and put in registers. This is how the museum can allow the building to go cold in the winter…which is how we would keep relative humidity up in the winter without introducing humidification…which would be expensive and could also have a negative impact on the wood structure in the form of condensation on wooden members and possible rot.

This system proposed for the collection areas of the house-- A "split, direct expansion, air conditioner with a hot gas reheat coil" -- is more expensive than other options. ‘Oh, well that seems like a good idea,’ you might be saying sarcastically to yourself. (If you did say that sarcastically to yourself you might want to take a break from reading this blog. I don’t want to be responsible for turning my readers into cynics.) Although there is a bigger upfront investment with this option, in the long run the museum would save money on utility costs. This system would operate more efficiently. Most HVAC systems dehumidify by supercooling – they use a refrigeration process to make the air so cold that water literally falls out of it (because cold air can hold less moisture than hot air). Then they use more energy to reheat the air to a comfortable temperature. This process is inefficient. The HVAC system we are considering would be different in that it would use the waste heat generated during the cooling process to reheat the air. Just think of your air conditioner and the waste heat that you vent out the window—we’d be capturing that waste heat and using it to raise the temperature of the “supercooled” air. Bottom line, it is the more efficient, cheaper, and greener option. There – now I’ve properly confused you all. You are welcome.

One of the rooms in the Collections Area Zone

In addition the museum will also need to purchase some fans to circulate the air on the second floor (the Collections Area Zone) as some rooms on that floor, the Master Bedroom, for instance, have no registers. Because they are less invasive by nature, fans would be preferable to running new ducts and putting in a new register in any of the rooms. Why put holes in perfectly good walls when you could just buy a fan to do the work for you?

This is a room in the Collections Area Zone which does not have a register or ducts in place and would therefore benefit from the use of fans to circulate the air.

The most important point I took from my conversation with the Director is that the proposed environmental control system, once in place, would mean one thing – FAREWELL ELECTRIC HEATER.

So long, farewell, auf Wiedersehen, adieu!

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