¶ Potentials of Night Sky Radiation to Save Water and Energy in the State of New Mexico
Governor Richardson's Water Innovation Fund — PSC #05-341-1000-0035 — Completed February 28, 2006
Produced by:
- Mark Chalom, Architect — Solar Design and Analysis, Santa Fe, NM
- Bristol Stickney, Solar Consulting — Cedar Mountain Solar
- Kate Snider, assistant and graphics
State Project Manager and Technical Advisor: Jim Sizemore, PE, Director, Water Rights Division, Office of the State Engineer
Through this grant process we have shown that Night Sky Radiant Cooling (NSRC) has great potential for utilization in the state of New Mexico as an alternative to air conditioners or swamp coolers. Utilization of NSRC can reduce the use of water and power at the time when the power grid is most stressed and water use is maximized for agricultural purposes in the state.
The goal of this grant was to explore the natural phenomenon of Night Sky Radiant Cooling as a way to save water and energy in the state of New Mexico. The research quantifies the potentials within the state and how effective NSRC is in the 11 climate zones in New Mexico.
The basic premise for savings is based on a well-designed energy-conserving home with a radiant heated slab cooled by unglazed swimming pool collectors on a flat roof serving as cooling radiators. The research found that an efficiently designed home in the hottest climate zones in New Mexico can be cooled entirely with NSRC.
Power savings for cooling an efficient 1800 sq ft home can range from 25% in Albuquerque to 89% in Carlsbad compared to conventional air conditioning.
- Executive Summary and Conclusions — project description, objectives, and findings
- History of Night Sky Radiant Cooling — from ancient Iran through present-day New Mexico
- Explanation of Night Sky Radiant Cooling — principles and formulas; tilt and wind correction factors
- Cooling Alternatives in New Mexico — evaporative cooling and air conditioning compared to NSRC
- Radiator Test Data — 10 collector types tested over 2 summers in Tesuque, NM; average "U" value of 1.66 BTU/hr·ft²·°F
- Statewide Savings Potentials — projections across 11 climate zones for a typical 1800 sq ft energy-efficient home
- Field Tested Systems Summary — installed NSRC systems and test data
- Water and Power Usage Comparison — evaporative cooling, air conditioning, and NSRC
- Calculator/Worksheet — explanation of inputs and summaries
- Appendix — references, state weather data, fuel cost escalation, quarterly reports
- NSRC can cool an efficiently designed home in New Mexico's hottest climate zones using only nighttime sky radiation.
- Researchers tested 10 different radiator/collector types over two summers in Tesuque, NM, at 5-minute intervals. Overall average cooling "U" value: 1.66 BTU/hr·ft²·°F.
- PNM publishes a water-use figure of 0.74 gallons per kWh for average power production — every kWh saved from NSRC also saves water at the power plant.
- Savings in kWh directly reduce NOx, SO₂, CO₂, and other pollutants from power generation.
- The coolest New Mexico climate zones may need only nighttime ventilation; NSRC is most impactful in Albuquerque and warmer zones.
| Zone |
Location |
Cooling kWh Reduction |
| 1 |
Red River |
minimal (ventilation sufficient) |
| 9 |
Albuquerque |
~25% |
| 11 |
Carlsbad |
~89% |
(Full zone-by-zone data in Section 6 of the report.)
Source: Governor Richardson's Water Innovation Fund, State of New Mexico, PSC #05-341-1000-0035.
PDF: 2006-02-28-potentials-nsrc-new-mexico.pdf