Thermo King TriPac Evolution (diesel APU)
Thermo King (Trane Technologies) · Apu · Diesel APU (auxiliary power unit)
What this component does
The Thermo King TriPac Evolution is one of the dominant diesel APUs (Auxiliary Power Units) for Class 8 sleeper-cab trucks. APUs provide cab heating, cooling, and 12V/110V electrical power for the driver's sleeper berth without running the truck's main engine. Anti-idling regulations in most US states + California ACT make APUs essentially mandatory for over-the-road operations. The TriPac Evolution holds approximately 35-40% APU market share, competing with Carrier ComfortPro and Idle Free. Saves fleets 1-2 gallons of diesel per hour of idle time vs running the main engine.
Specifications
- Manufacturer
- Thermo King (Trane Technologies)
- Category
- Apu
- Subtype
- Diesel APU (auxiliary power unit)
- Truck class
- Class 8
- Production
- 2010–present
- Applications
- Sleeper cab driver comfort — heating, cooling, electrical power without idling main engine
Design and engineering
Small diesel engine (1-1.5 L typical) mounted in the truck's frame. Drives a generator for 12V (battery charging) and 110V (cab outlets, microwave, TV). Refrigerant-based cabin climate control (cooling) + diesel-fired bunk heater (heating). Independent of main engine.
Generations
- TriPac Evolution Original (2010–2018)Launch.
- TriPac Evolution with EPA Tier 4 Final (2019–present)Compliant with EPA Tier 4 emissions, refined controls, DEF integration.
Reliability and longevity
Strong reliability. 12,000-15,000 operating hours typical service life before major overhaul.
Common problems
Diesel engine wear at high hours (similar to main engine — needs oil/filter PM). EPA Tier 4 emissions complexity. APU theft from parked trucks is a recurring fleet problem.
Maintenance schedule
Oil/filter every 750-1,250 operating hours (Thermo King schedule). Annual PM check. EPA Tier 4 DEF top-up.
Pros and cons
Pros
- ✓Industry-standard APU choice
- ✓Saves 1-2 gal/hour vs main engine idle
- ✓Meets state anti-idling rules
- ✓Thermo King dealer network
Cons
- !Upfront cost $9,000-13,000 installed
- !Adds ~400 lb to truck weight
- !EPA Tier 4 emissions service complexity
- !APU theft risk