1. Keeping Doc’s Cool, Dry & Happy
“Can I Do The Job With What I’ve Got?”
David N. Schurk DES., CEM., LEED-AP., CDSM., CWEP, SFP., CIAQM., HCCC.
National Healthcare Strategic Accounts Manager
Carrier Corporation

3. Connecting the Dots…How can we Help?
Identify Problems
Offer Solutions

4.
Narrative Notes:
Source: ASHRAE

5. Source: ASHRAE

6. SPACE = 64°Fdbt @ 58% rh (49°Fdpt)
Older OR’s = sq ft.
New General OR’s = sq ft.
Neuro/Ortho OR’s = sq ft.
Hybrid OR’s = sq ft.
15°F
Outdoor
ASHRAE
HVAC Design Manual
for Hospitals and Clinics
Source: ASHRAE

7. “Typical internal cooling load is 2 to 3 tons
“Typical internal cooling load is 2 to 3 tons. With an air change rate of 20 and supply air at 47°F to 50°F [8.3°C to 10.0°C], the system can provide 6 to 7 tons of cooling, roughly twice the actual load. Thus, in almost all operating rooms, the required ACH drives the size of the HVAC system, not the internal load”.
Source: ASHRAE

8. REHEAT

9. “Although FGI and ASHRAE recommend a temperature range of 68°F to 75°F at 20% to 60% rh, many surgeons request temperature & humidity settings outside of these ranges.
Inability to maintain low OR temperature is probably the number one complaint by surgeons to facility engineers”.
Source: ASHRAE

10. “The Point of Diminishing
“I Want it Colder!”
Aka: I Want it Drier
40%rh
“The Point of Diminishing
Complaint” (DNS)
Many times, lower RH values may be necessary in order to create an environment which can absorb perspiration and remove heat through multiple layers of clothing and into the surrounding dry air.
Source: ASHRAE

11. 70°F 65°F 60°F 53%RH 63%RH 75%RH 42°F CWT Space#1 Space #1 Space #1
At the same dew-point, as the space temperature goes down the relative humidity goes up.
HUMIDITY
TEMPERATURE
70°F
65°F
60°F
53%RH
63%RH
75%RH
Too Warm
Cool & Clammy
Noncompliant
Cold & Clammy
Noncompliant
42°F CWT
Space#1
Space #1
Space #1

12. 70°F 65°F 60°F 37%RH 44%RH 53%RH Space#1 Space #1 Space #1 Too Warm
At the same dew-point, as the space temperature goes up the relative humidity goes down.
HUMIDITY
TEMPERATURE
70°F
65°F
60°F
37%RH
44%RH
53%RH
Too Warm
Better
Best
Space#1
Space #1
Space #1

13. Traditional Mechanical Refrigeration Systems
COOLED
WARM B B
Dry Bulb = Wet Bulb = Dew Point
Air Leaves CC “Saturated”

14. 70°F db @ 50% RH 60°F db @ 40% RH 51°Fdpt 48°Fdpt 41°Fcwt 36°Fdpt

15. Space °F DB Space RH% °F DP SAT °F DB CWT Reheat Chilled Water70 50
50.5
47.5
40.5
17.5
Yes 40
44.6
41.6
34.6
23.4
Glycol 68
48.7
45.7
38.7
17.3
42.8
39.8
32.8
23.2 66
46.9
43.9
36.9
17.1
41.0
38.0
31.0
23.0 64
45.0
42.0
35.0
17.0
39.2
36.2
29.2
22.8 62
43.2
40.2
33.2
16.8
37.4
34.4
27.4
22.6 NA 60
41.3
38.3
31.3
16.7
35.6
32.6
25.6
22.4
Assumptions: Space latent load requires 3°fdpt depression, CWT to SAT approach is 7°fdb, SAT to space is 5°fdb ΔT.
Note: Actual space load calculations are required to ensure performance, the above is only for approximation of temperatures.

16. Houston, TX 60°Fdb @ 40% rh = 35.64°Fdpt Supply Air = 32.64°Fdpt
NOTE: If the operating room and it’s ventilation air is not properly dehumidified, anytime outdoor weather conditions are above the horizontal RED line moisture will be added to the space.
40% rh = 35.64°Fdpt
Supply Air = 32.64°Fdpt

17. Dallas, TX 60°Fdb @ 40% rh = 35.64°Fdpt Supply Air = 32.64°Fdpt
NOTE: If the operating room and it’s ventilation air is not properly dehumidified, anytime outdoor weather conditions are above the horizontal RED line moisture will be added to the space.
40% rh = 35.64°Fdpt
Supply Air = 32.64°Fdpt

18. Show Them the Money!
“Proper environmental control insures our hospital will maintain the surgical procedures that yield the most profit without fearing the loss of surgeons to competing facilities where OR conditions are more comfortable”.
Source: Chief of Facility Engineering

19. Where Do I Go From Here?

20. 33°F LCWT vs. 42°F LCWT < 12%-18% CAPACITY & EFFICIENCY
Existing Chillers May be Incapable of Providing Colder Leaving Water Temperatures

21. Low-Temp & Glycol Chillers
+ Capable of lower DPT’s
+ Traditional refrigeration/HVAC
+ Understandable by most
- Leaving air temps above freezing
- Slightly complicates the system
- May requires glycol
- Lowers chiller efficiency
- Reduces chiller capacity
- Intensifies reheat
Source: ASHRAE

22. Solid Desiccant System Schematic
From Outdoors
To Outdoors
To Space
To Be Dehumidified
Post-Cooled
Pre-Cooled

23. To Space
To Outdoors
Dehumidifies
Humidifies
May Eliminate Post Cooling
May Eliminate Reheat
Free Regen Heat (HRC)
“Sterilizes”
TD “Eloquent”
To Be Dehumidified
From Outdoors

24. “A desiccant technology that provides precise dehumidification,
Humidification, and near sterilization of air flow provided to critical process/procedural areas”

25. * LD Dehumidifier OR Air-Handler OA Air-Handler Operating Room
Regenerator
OA Air-Handler
Filter
Cooling
Fan
Filter
Htg
Clg
Fan OA
Conditioner RA SA
Humid
Dehumid *
Operating Room
Heat-Recovery
Chiller

27. “There is an ethical dimension to our failure to adopt technology, products, or protocols that improve the quality or duration of life - it is the moral equivalent of withholding life-saving medicine from a patient in need.
The work of improving the delivery of healthcare is both urgent and necessary.”
Sachin H. Jain MD, MBA President/CEO, CareMore Health System; Adjunct Professor, Stanford University School of Medicine.
Thank-You