Brian's Tips

Brian Lomel, PE, CxA, LEED-AP BD+C serves on the GMBHA Sustainability Committee and has over 20 years of consulting experience as a professional mechanical engineer in tropical climates.  He is a principal at TLC Engineering for Architecture, a 55+ year-old Florida Company, with 300+ employees including 80+ professional engineers and 90+ LEED accredited professionals.

Tropical Sustainability Tips

Miami-Dade is one of 3 counties in the continental US that is classified as Climate Zone1A (Tropical, humid).

What does that mean?  It means that many strategies for energy reduction and hotel operation that are beneficial in other parts of the country are NOT recommended for our climate.  While the temperature may feel similar to Southern California, by the numbers, San Diego is a Dry, Zone 3 environment. The International Energy Conservation Code (IECC) has classified and defined the Climate Zones throughout the United States as shown in this map.

Climate Map

The following recommendations ARE appropriate for our Tropical climate in Miami-Dade.

1. The largest single energy consumption component of a typical hotel is artificial lighting, because the majority of the energy provided to the light fixture becomes waste heat for the HVAC system to cool.  A small portion of the energy actually becomes light.

2. Daylight, when harvested correctly, produces even light levels, prevents radiation heat, prevents glare and is fully integrated with the artificial lighting controls.  Under these conditions, it can:

    a. Increases worker productivity and reduce illness/absenteeism.

    b. Increases retail sales.

    c. Be the largest single energy reduction strategy, when coupled with dimming controls.

3. Poorly designed daylight harvesting that causes glare has been shown to reduce retail sales and worker productivity.

4. An Occupancy Sensor installed in Guest rooms can be used to reduce lighting and HVAC energy.

5. Older/historic hotels can use the installation of an inner window to reduce:

   a. Energy lost due to moisture migration into guest rooms.

   b. Reduce noise from the exterior

   c. Provide additional level of security

   d. Reduce Energy Use by redirecting radiation heat to the exterior.

6. Evaporative mist “swamp coolers” are not ideal for high wet bulb tropical climates

7. Ground source geothermal heat pumps are not ideal for high temperature water table areas like Miami Beach.

8. With 62” of annual rainfall, a stormwater collection system should meet most irrigation needs.

9. The amount of condensate from a mid-rise hotel or taller could be as much as 3x the water generated by rainfall.  If collected efficiently could reduce cooling tower or irrigation water demands.

10. When in doubt, add a meter and track the energy/water flow.

11. Light color walls and roof reflect radiation heat.  Target and SRI above 78 for flat roofing, 29 for steep sloped roofing and above 29 for hardscape materials.

12. Insulation values higher than R-20 for the roof and R-11 for the walls may have an undesirable payback of longer than 20 years.

13. The top 3 energy consumption targets are radiation through the glass, artificial lighting and ventilation air dehumidification.

14. The ambient vapor drive will push moisture through a concrete wall.  Cracks and openings will accelerate this moisture penetration.  Seal openings and cracks in the envelope.

15. Vapor retarding systems should be applied to the exterior side of the wall.

16. Avoid vinyl, or any moisture inhibiting wall covering on interior surfaces of envelope walls.  The moisture travelling through the wall will be trapped, condense and eventually encourage mold growth.

17. Pressurizing a hotel, with respect to the outdoors, with clean dry air, reduces the amount of moisture infiltration.  Many strategies begin with pressurizing the corridors.

18. Centralizing a ventilation system will allow for energy conservation through heat reclaim as well as reduce risk for moisture damage in the spaces by pressurizing the building with dry air.

19. Solar water heating is multi-thousand year old technology.  It is always appropriate for a hotel if the “hurricane-proofing” structural costs do not make the ROI unbearable.

20. Creative Shading in public exterior spaces can make outdoor gathering more conducive, because radiation heat is the main driver of discomfort, not high temperatures.