# Refrigerant Undercharge Detection:

## 30% Energy Waste Identified & Corrected via Continuous Monitoring

### Mitsubishi MXZ-SM36NAMHZ | Colorado Deployment

| UNDERCHARGE | EFFICIENCY GAIN | ANNUAL WASTE | CO2 AVOIDED |
| --- | --- | --- | --- |
| 40% refrigerant deficit | ~30% energy intensity reduction | ~2,400 kWh ~ $360/yr at $0.15/kWh | 1.26 MTCO2/yr (eGRID RMPA) |

## Temperature-Normalized Energy Analysis: Before vs. After Service

### Key Findings
Thalo’s continuous cellular monitoring detected anomalous power draw on a Mitsubishi MXZ-SM36NAMHZ VRF heat pump. Field inspection confirmed a 40% refrigerant undercharge. After correction:

- Energy intensity: 1.59 → 1.11 kWh/°F-day (−30%)
- Monthly winter savings: ~480 kWh ($72/mo)

\( R^{2} \) Daily kWh normalized by heating degree-days (base 65°F). Before/after compared via OLS regression with R² goodness-of-fit.

- Monthly winter savings: ~480 kWh ($72/mo)
- Avoided emissions: ~1.26 MT CO₂/yr (≈ 3,200 mi driving)

This fault would have gone undetected indefinitely without telemetry. 
Field surveys find 78% of installed systems have charge issues.

## Fleet-Scale Impact (24,000 units)

Assuming 25% of units have charge faults at half this severity: ~7.2M kWh/yr wasted, ~$1.1M/yr excess electricity, and ~3,790 MT CO₂/yr of avoidable emissions.

## Why This Matters

Colorado’s RMPA grid (1,159 lbs CO₂/MWh) is 43% more carbon-intensive than the national average. Every kWh saved here carries outsized climate impact.

## References
1. Domanski, Henderson & Payne (2014). NIST TN 1848: Improper installation increases HVAC energy use ~30%. Refrigerant charge identified as leading fault.
2. Kim & Braun (2012). Int. J. Refrigeration: 25% undercharge → 15% COP loss; 40% interpolates to 25–40% degradation. Our 30% finding sits mid-range.
3. Hu & Yuill (2020). Applied Thermal Engineering: Heat pump COP reductions up to 34% from refrigerant faults within normal safety limits.
4. Mowris et al. (2004) / EPA eGRID (2023). 78% field undercharge prevalence (Phoenix). RMPA subregion: 1,158.9 lbs CO₂/MWh (eGRID 2021 data).