Enclosure Thermal Control

Data Archive

Enclosure Thermal Control

Project Goals

The goal of the Enclosure Thermal Control Project is to remove or control heat sources in or near the HET enclosure for the purpose of improving the seeing and image quality due to local air flow.

The Snufalufagus Project is one of the subprojects and will attempt to remove all waste heat generated on the tracker. Heat sources include the PXL cameras, the LRS electronics, various wall warts, etc. Gordon Wesley and Paul Peterson are working on this one. The project name comes from one of the early boxes that was very heavy and had a large hose running out from it. Much like Mr. Snufalufagus on Sesame Street.

Operation Chrome Dome is also one of the subprojects. John Good gets to manage this one. Its goal is to coat the exterior of the HET dome with Aluminum tape. This is expected to reduce the supercooling of the dome to the night sky with the result that dome seeing will improve. There are a total of 332 panels that will need to be taped up. The following pictures and table shows our current progress.

Before Chrome Dome
25 May 2002
Latest Chrome Dome
27 Feb 2003

Date Panels
Complete Percent
Complete
12 Nov 2003 ??? 100%
18 Dec 2002 309.5 93.9%
16 Dec 2002 307.5 92.6%
14 Dec 2002 297.5 89.6%
13 Dec 2002 292.5 88.1%
11 Dec 2002 285.5 86.0%
10 Dec 2002 282.5 85.1%
7 Dec 2002 277.0 83.6%
6 Dec 2002 265.0 79.8%
5 Dec 2002 260.0 78.3%
2 Dec 2002 254.0 76.5%
25 Nov 2002 245.5 73.9%
24 Nov 2002 244.5 73.6%
23 Nov 2002 243.5 73.3%
22 Nov 2002 226.5 68.2%
21 Nov 2002 202.5 61.0%
20 Nov 2002 187.5 56.5%
19 Nov 2002 169.5 51.1%
18 Nov 2002 150.5 45.3%
17 Nov 2002 136.5 41.1%
15 Nov 2002 112.5 33.8%
14 Nov 2002 100.0 30.1%
13 Nov 2002 83.5 25.2%
12 Nov 2002 67.5 20.3%
11 Nov 2002 51.5 15.5%
8 Nov 2002 40.5 12.2%
7 Nov 2002 30.5 9.2%
6 Nov 2002 22.5 6.7%
3 Nov 2002 15.5 4.6%
30 Oct 2002 14.5 4.4%
29 Oct 2002 10 3.20
28 Oct 2002 6 1.8%
23 Oct 2002 4.5 1.3%

Project Activities

12 Nov 2003 Enclosure Dome Finished !!!

Paul, Robert and Michelle finished off the last of the work on top of the enclosure dome today. As a celebration they repelled down the outside of the dome at the end. There are plenty of pictures available as we had both Edmundo and Chris Wilkenson with cameras.

Edmudo Balderrama's pictures

Chris Wilkenson's pictures

11 Nov 2003 Good Weather again

Robert and Paul continued work on the dome. There are now only three panels up top remaining to be covered. If the weather remains good this week we should finish the dome.

4 Nov 2003

Paul worked on his own this morning before high winds shut things down. He completed two triangles and most of a mushroom.

31 Oct 2003 Happy Halloween No work today

No work today. Paul is out of pocket.

30 Oct 2003 Continuing work

Michelle and Paul back on the dome. High winds prevented work earlier this week. Most of the remaining work consists of the small panels and the muchrooms over the vents.

22 Oct 2003 Michelle Graver starts work

Michelle Graver, our new Telescope Operator, and Paul Petersen have gotten back to work on the final activities required to finish the work on top of the dome. Michelle has gone through the training for the rope work required to work up top. She and Paul finished 4 panels today.

25 Jan 2003

2.5 panels completed on top.

24 Jan 2003

3.5 panels completed on top.

18 Dec 2002, 2 panels completed before high winds shut us down

The morning started out marginally with winds around 25 mph. The crew went up and managed to complete 2 panels before the winds jumped to 50 mph. Snow and rain ended that day.

17 Dec 2002, High winds prevent work

Winds gusting to 40-50 mph prevented any work on the dome today. The percentage complete table above was recalculated based on a total of 332 panels rather than 314. See the entry for 6 Dec when this count was revised.

16 Dec 2002, Good weather today

Despite marginal winds which came close to exceeding the criteria, the crew managed to complete 10 panels today. Robert claims we only have 16 more panels to reach with the manlift.

15 Dec 2002, No work due to high winds

14 Dec 2002, High winds limit work.

Rex and Louis completed 5 panels today before high winds stopped work.

13 Dec 2002, 7 panels completed today

12 Dec 2002, High winds prevent work

The winds picked up quickly this morning. Averaging 30 and gusting to 40 mph, they prevented any work on Chrome Dome today.

11 Dec 2002, Only 3 panels complete due to increasing winds

Jimmy and Louis were only able to complete 3 panels today as the winds started to pick up this afternoon. Unfortunately the higher we work the less shielding the dome affords and so the winds limits decrease.

10 Dec 2002, 5.5 panels completed today

Jimmy and Louis were able to complete 5.5 panels today. We only have the upper ones remaining. There are harder to work on so progress will be slower. Weather permitting, we are going to try to finish with the manlift by Christmas.

9 Dec 2002, No work due to high winds

8 Dec 2002, No work due to poor weather

7 Dec 2002, Good work today

Despite a late start today, Rex and Jerry were able to finish an additional 12 panels. Weather was excellent; cool and clear with only light winds.

6 Dec 2002, Continued progress

Cold weather this morning caused a slow start. Only 5 triangles were finished today. However, Robert reports that only 55 triangles and 4 rectangles remain below the upper shutter ring. There are only 10 triangles within the ring that must be completed. Assuming our work counts are correct this means that there are actually 332 triangles to be taped rather than the 314 quoted above. We are then 80% complete today rather than 85%. In any case if the weather holds, we could be done by Christmas.

5 Dec 2002, Partly bad weather

Freezing fog prevented work this morning but the sun came out this afternoon. Six panels were completed today.

4 Dec 2002, Bad weather

3 Dec 2002, Bad weather

Wet, cold and windy today.

2 Dec 2002, Back to work

We are back to work following the Thanksgiving Holiday. The weather was warm with no breeze this morning. Winds picked up this afternoon and shifted to the East. We moved the large manlift to the west side and continued work with no problem. 8.5 panels were completed as well as 8 rectangles. This completes the rectangles that need to be done. We are now over 80% complete on the panels.

25 Nov 2002, More rectangles complete

Only one triangle today but 8 rectangles around the shutter were complete. Only one more rectangle on the shutter to go now.

24 Nov 2002,

Weather starting to deteriorate. Only one triangle and 5 rectangles completed today.

23 Nov 2002,

Tom Brown reports that 17 triangles and 8 rectangles were completed today. Your roving correspondent is in Cloucroft this week so reports may be sporadic.

22 Nov 2002, 24 Panels completed today

Good weather, continued work. Gordon took the following pictures of the work to date.

Gordon Wesley returned to Austin following his work on the Snufalufagus project. He send the following trip report.

"This is a brief report of the work done this week to get the heat from the tracker and the tracker electronics moved outside. The contractor, Keith Grigsby, and his men arrived Wednesday morning and we began installing the outer tube through the pintle bearing. We were successful in getting the outer tube installed and the box on top of the center hub installed on Wednesday. The bottom of the box has a Teflon bearing to guide the outer tube as the telescope raises and rotates. The top of the box has a rounded horn (for the lack of a better word), to accept the fibers. The end of the day Wednesday had the outer tube and box in place and the fibers safely located so the telescope could be used.

Thursday the inner, 4-inch tube and the final duct work at the ceiling of the spectrograph room were installed. The exhaust fan was also tested with good results. The vertical and rotary motion of the telescope was tested and worked fine. The bearing/guides for the inner and outer tubes worked as expected. With respect to a fixed reference, the inner tube, the junction box, and the ducts under the primary mirror rotate.

Friday a transition box was attached to the side of the hub box and a 14-inch round duct was installed along a wide-flange beam up the back of the telescope structure under the primary mirror to a point above the tracker electronics box where a Y-duct was installed. From the "Y" a 12-flexible duct was run to the fan in the electronics box and the 16-inch flexible hose from the tracker was to the other side of the "Y".

With the 12-inch fans from the electronics box and the tracker running and the exterior fan on, air flowed into the box through a large inspection opening in the hub box, indicating the exterior fan had the capacity to pull all the air coming from the 12-inch fans and additional air from the room. This was a good sign.

I did not hear any whistling from the air flow, but you can tell air is moving. The duct in the basement is pretty well sealed. I don't think the hub box got as much attention, but with the extra capacity, it may not be such a bad thing. Perhaps we can pull a bit of air from the pool inside the pier.

I believe everything is pretty well anchored and ready to go. Things I would watch include checking to make sure the inner and outer tubes are turning and moving up and down easily in their Teflon bearings and dirt build up in the bearings that could lead to binding. There is a side inspection cover in the duct in the spectrograph room that should make it easy to check. The inner tube is a 12-foot long, 4-inch diameter tube that is being driven from the top of the hub box. Gravity is on our side, and with the Teflon bearing at the bottom guiding it, it should not see much torque on it. If a problem arises it should be looked at to make sure it is intact.

I move all the remaining duct material in the storage room up to the shop. I put the straight pieces of duct on top of the cabinets. I could not figure out a good place to put the other fittings, so I stacked them in one place. There is a bundle of sheet metal straps that are probably Keith's, but I don't know if he would want to drive all the way here to get them. They are wrapped in duct tape. Heaven help the person that releases that can of worms.

That's about it for now. I have pictures if anyone wants to see them. Thanks to everyone who helped get this together and dealt with our mess."

21 Nov 2002, Good weather, bad manlifts

More good weather, more panels finished. The manlifts continue to be a problem and are slowing us down. Today we completed 15 due to the manlift. The crews also started to work on the rectangular panels around the lower edge of the dome as well as around the shutter. There are 74 of the large rectangular panels and 6 (8%) were finished today.

20 Nov 2002, More good weather, bad manlifts

Completed 18 panels today but were slowed down by a failed O-ring in the hydraulics of the big manlift and by problems with the small manlift.

19 Nov 2002, We exceed 50% completion today

Good weather today allowed us to finish 19 panels. We achieved 50% of the panels coated today. Paul and Robert did begin work on the mushrooms at the top of the dome today as they were very sore from yesterday's work hanging on the ropes.

18 Nov 2002, Some high winds but still got 14 panels

This morning was cloudy and windy so we did not work. However after lunch the winds died down and we set to work with three crews. Rex and Joe worked in the 135 foot manlift, Jimmy and Louis worked in the 80 foot manlift, with Robert and Paul working off the ropes. All together they got 14 panels complete today. Robert and Paul believe they can get 5 panels a day working off the ropes.

17 Nov 2002, New record

Good weather today. Jimmy and Louise finished 13 panels while Jerry and Robert got 11 done. This is a new record of 24 panels in one day.

16 Nov 2002, More bad weather

Snow, ice and cold temperatures prevented work this morning.

15 Nov 2002, Twelve more finished

Today started out well but towards noon the winds started to pick up. The small manlift was protected by the dome however the large manlift was buffeted quite a bit. Twelve and a half panels were completed today.

14 Nov 2002, 100 panels complete today

Good weather with occasional high winds. The teams completed 16.5 panels which means that a total of 100 panels have been completed as of today.

13 Nov 2002, We continue along

Good weather today allowed both manlift teams to operate. Sixteen panels were completed today.

12 Nov 2002, Pictures

Sixteen panels completed today. Two crews in operation. John Good did some temperature tests inside the enclosure during the night.


View from West	View from South

11 Nov 2002, Good weather finally

Finally had good weather today although it was cold. Jimmy and Louis completed 9.5 panels today. The second man lift arrived today. This one has a 135 foot extension and will be used to reach the top of the dome. Rex and Robert will be the team for it. They only finished 1.5 panels done today but say that were busy getting the new lift set up and working. We'll see tomorrow which group does the most panels. Some new pictures of the activities are available.

Chrome Dome activity.

Both manlifts in operation

Jimmy and Louis measuring foil

Close up of both manlifts

Wide angle shot of both manlifts

Art shot of the 135 foot lift

Sunset shot of work to date

Yet another sunset shot of our work

Post sunset shot of work to date

10 Nov 2002, High winds cause damage

Extremely high winds today (50mph gusting to 70 mph) prevented any work on chrome dome. Theses winds also destroyed some of the exterior work on the Snufalufagus project. The following pictures show the damage to the exterior vents that took place.

Wind damage to exhaust ducts.

Damage to fallen section

Fallen section of pipe on the ground

Closer view of failed section

Support fixtures and fallen section

Elbow joints

9 Nov 2002, High winds prevent work

High winds prevented weekend work on the chrome dome.

8 Nov 2002

Ten panels completed today. The crew must be learning something.

7 Nov 2002

Eight panels completed today.

6 Nov 2002

Seven panels completed today.

5 Nov 2002, High winds today

Clear sky and cold temps with a 50 mph wind this morning prevented work on the dome. Winds had settled to 30 mph by afternoon, still too high to allow work.

4 Nov 2002, Some clearing today

The weather started to clear this afternoon. Jimmy and Louis went up in the manlift and completed one panel. Weather is expected to be better the rest of the week.

1 Nov 2002, Still foggy and raining

No exterior work done on the dome due to rain and fog today.

31 Oct 2002, Happy Halloween, No work due to fog and rain today.

No exterior work done on the dome due to rain and fog today. We had a cold front move in last night. Robert and Paul are spending time rearranging their equipment.

Gordon Wesley sends the following trip report for the work done this week on Snufalufagus.

"Keith Grigsby and crew began installing the duct and fan for taking the heat removed from the top of the tracker and moving it outside the dome.

The fan was installed on the exterior wall above and to the right of the west doors. Ducts were run through the electrical storage room and into the spectrograph room, to within 6 feet, or so, of the pintle bearing. Ducts were also run around the northwest side of the exterior of the building. The ducts are currently tied in place and covered. Keith was planning to return today to permanently anchor the ducts and install the pintle bearing ducts. However, I realized a flaw in the design yesterday and will have to get a couple of parts re-made in Austin before work can continue. This will take 2-3 days. The ducts in place should not present any problems to normal operation. Let me know if you see any problems.

With the MARS2 design review next week, I don't expect to be ready to finish the work until at least the following week. Unfortunately, Keith being the business person he is, has scheduled other work with the expectation we would be finished this week, so final work will have to be coordinated with the HET schedule and Keith's schedule. I will be making the contacts to schedule the work.

For the time being Keith is leaving some of his equipment and materials in the shop. He did not want to haul it back and forth to Alpine and has other equipment he can use. His equipment can be set aside for storage."

30 Oct 2002, Four and half panels completed today.

Weather was good today. Paul, Robert, Jimmy and Louis finished four and a half panels today. Paul and Robert are getting faster though it is more difficult as they try to get the tape under the shutter rail.

Most of the exterior work was completed on the Snufalufagus project.

29 Oct 2002, More work today.

Despite some winds we worked from the manlift and the top today. Four additional panels completed. We continue to develop the procedures for the guys on the ropes. Work is not going quite as fast as John had hoped.


Robert and Paul considering procedures on top of the dome	Jimmy and Louis working from the manlift basket	The whole enchilada. There are a lot of panels to do

Most of the duct work was installed in the spectrograph room today.

28 Oct 2002, Weather clears up.

The bad weather moved out of here today around noon. Although somewhat windy this afternoon we did manage to get one and a half panels taped up along the lower portion.

Jim installed 7 sets of temperature sensors up the right rear leg of the structure. The purpose of this chain is to obtain information on the stratification of the air layers in the enclosure, both before and after the installation of the aluminum tape.

Gordon Wesley supervised Keith Grigsby and crew from ??? as they installed part of the Snufalufagus ventilation system. The exterior fan is now mounted.

24-25 Oct 2002, Rainy Days.

Rain, wind and fog from Hurricane Kenna and a cold front in the North prevented any outdoor work these days.

23 Oct 2002, Starting the project.

The first four panels reachable from the manlift were finished today. An additional panel was started on the upper portion where we have to use ropes. Today's work was designed to practice the techniques to be used during the project. Sorry we have no pictures. Our digital camera is dead. We have a new one on order but it has not yet arrived.

16 Oct 2002, The plan develops.

John Good presented additional installation plans at the weekly HET Telecon. His presentation is given in HET16Oct2002.ppt.

2 Oct 2002, More test results.

John Good presented additional results on the Low-E testing to the HET Telecon this morning. His presentation is given in LowE_TestResults2.ppt.

25 Sept 2002, Test results for Low-E coatings.

John Good presented his test results for the aluminum tape and the Low-E coating. The aluminum tape wins hands down. John's presentation is given in LowE_TestResults.ppt.

24 Sept 2002, Test of Exterior Dome Coatings.

John Good, Robert Poenisch, and Paul Peterson installed aluminum foil tape to one dome panel and painted another with an improved paint. We'll see how they last in the West Texas weather.

Here's a picture of John and Robert signaling their success on the HET dome.

18 Sept 2002, Planning the Coatings Test.

John Good presented a plan at the weekly HET Telecon for testing two types of coatings, aluminum tape and a Low-E paint. His test plan is presented in LowE_Coatings.ppt.

4-5 Sept 2002, Enclosure thermal measurements

John Good used a calibrated surface thermometer to map temperatures on the HET dome skin, enclosure floor, and spectrograph room. His PowerPoint presentations are available as 4Sep2002Data.ppt and 5Sep2002Data.ppt.

31 May 2002, Initial calculation, Ed Robinson.

Ed Robinson did the calculations that showed how important it was to control the heat flow through the thin skin of the dome. His conclusion was that heat loss through the dome skin would create a lot of cold air that would fall through the light path. A copy of his paper, Conductive Heat Flow in the HET Dome is available in postscript format.

Last updated: 31-Oct-2003