When virtualizing legacy servers, the cooling cost calculation breaks down into three fundamental components:
// Pseudocode for cooling cost calculation
function calculateCoolingCost(serverWatts, coolingEfficiency, electricityCost) {
const btusPerHour = serverWatts * 3.412; // Conversion factor
const tonsOfCooling = btusPerHour / 12000;
const hourlyCost = (tonsOfCooling / coolingEfficiency) * electricityCost;
return hourlyCost * 24 * 30; // Monthly cost
}
From APC logs showing 880W draw:
- 880W × 3.412 = 3002.56 BTU/hr
- 3002.56 ÷ 12000 = 0.25 tons cooling required
Modern HVAC systems typically have efficiency ratings (EER) between 8-12. For calculations:
// Example with EdgeStar AP14000HS (EER 10.5)
const coolingEfficiency = 10.5;
const electricityRate = 0.12; // $/kWh
const monthlyCost = calculateCoolingCost(880, 10.5, 0.12);
console.log(Estimated monthly cooling cost: $${monthlyCost.toFixed(2)});
While ambient temperature affects absolute cooling requirements, the server-to-cooling ratio remains constant. What changes is the baseline HVAC workload.
function tempAdjustedCoolingCost(baseWatts, ambientTemp, targetTemp, ...params) {
const deltaT = ambientTemp - targetTemp;
const adjustmentFactor = 1 + (deltaT * 0.02); // 2% per °F above target
return calculateCoolingCost(baseWatts * adjustmentFactor, ...params);
}
For data center planning, consider this Python class:
class ServerCoolingCalculator:
def __init__(self, server_watts, eer=10.5, cost_per_kwh=0.12):
self.server_watts = server_watts
self.eer = eer
self.cost_per_kwh = cost_per_kwh
def calculate_btu(self):
return self.server_watts * 3.412
def monthly_cost(self, hours=24*30):
cooling_power = self.calculate_btu() / self.eer
return (cooling_power / 1000) * self.cost_per_kwh * hours
Cross-validate your calculations with:
- UPS power draw metrics
- HVAC system runtime logs
- Utility bill analysis during peak loads
Modern virtualization reduces cooling needs through:
- Dynamic power management (DVFS)
- Thermal-aware workload scheduling
- Hot/cold aisle containment
When virtualizing legacy hardware, understanding cooling costs requires mastering three key conversions:
// Conversion formulas in Python
def watts_to_btu(watts):
return watts * 3.412142
def btu_to_ton_hours(btu):
return btu / 12000 # 1 ton = 12,000 BTU/hr
def kwh_to_cost(kwh, rate=0.12):
return kwh * rate # Default $0.12/kWh
Data center cooling isn't 1:1 efficient. Consider these variables:
- PUE (Power Usage Effectiveness) of your facility (typically 1.5-2.0)
- CRAC unit efficiency (modern units achieve 0.7-0.9 kW/ton)
- Ambient temperature differential (ΔT between intake and exhaust)
Let's calculate cooling costs for your 880W server:
# Sample calculation
server_watts = 880
cooling_pue = 1.8 # Average data center
electric_rate = 0.14 # $/kWh
crac_efficiency = 0.8 # kW/ton
btu = watts_to_btu(server_watts)
ton_hours = btu_to_ton_hours(btu) * 24 # Daily
cooling_kwh = ton_hours * crac_efficiency * cooling_pue
daily_cost = kwh_to_cost(cooling_kwh, electric_rate)
print(f"Daily cooling cost: ${daily_cost:.2f}")
# Output: Daily cooling cost: $8.11
For more accurate modeling:
# Temperature-adjusted calculation
def adjusted_cooling(base_btu, ambient_temp, target_temp=72):
temp_factor = max(1, (ambient_temp - target_temp) / 10)
return base_btu * temp_factor
Implement real-time monitoring with tools like:
# Pseudocode for cooling optimization
while True:
current_temp = get_server_inlet_temp()
if current_temp > threshold:
increase_cooling()
else:
apply_aisle_containment()