Buy Thermo King MD-200 Online
The Thermo King MD-200 is a truck refrigeration unit designed for medium-duty straight trucks, typically those with box lengths of 12 to 20 feet, used in local and regional delivery of perishable goods. Unlike the trailer-focused SB-230, the MD-200 caters to smaller fleets or urban operators needing reliable cooling for fresh or frozen cargo—think grocery deliveries, catering services, or small-scale pharmaceutical transport. Introduced as part of Thermo King’s MD (Medium Duty) series, it bridges the gap between lighter units like the MD-100 and heavier options like the MD-300, offering a balance of capacity, efficiency, and compactness.Buy Thermo King MD-200 Online
Launched in the early 2000s (with refinements over the years), the MD-200 reflects Thermo King’s decades-long expertise in transport refrigeration, dating back to its founding in 1938 by Joe Numero and Frederick McKinley Jones. By 2025, it’s a mature product, widely available in the used market and still supported by Thermo King’s extensive dealer network. It’s prized for its durability, ease of maintenance, and ability to operate in diverse climates, from scorching summers to frigid winters. The unit comes in various configurations—diesel-only (MD-200 30) or diesel with electric standby (MD-200 50)—and uses R-404A refrigerant, though newer regulations are nudging operators toward alternatives.Buy Thermo King MD-200 Online
The MD-200’s purpose is straightforward: keep cargo at precise temperatures (typically -20°F to 80°F) while minimizing fuel use and downtime. It’s not a cutting-edge electric unit like the E-200, but its proven mechanical design and optional electric standby make it a practical choice for cost-conscious operators in 2025.
Historical Context
Thermo King’s MD series emerged as the company expanded beyond trailers into truck-based refrigeration. The MD-200, likely debuted around 2003-2005, arrived during a period of rising fuel costs and stricter emissions rules, like the EPA’s Tier 2 and later Interim Tier 4 standards. It built on the success of earlier MD models by integrating a more efficient engine (the TK370) and advanced controls (initially Thermoguard, later upgraded options). Competitors like Carrier Transicold’s Supra series pushed Thermo King to refine the MD-200 with features like extended maintenance intervals (EMI-2000) and CYCLE-SENTRY, a fuel-saving stop-start system.Buy Thermo King MD-200 Online
By 2025, the MD-200 isn’t the latest tech—full-electric units are gaining traction—but it remains relevant for its reliability and lower upfront cost. Its design prioritizes function over flash, appealing to operators who value uptime and Thermo King’s service infrastructure over experimental innovation.
Design and Core Components
The MD-200’s design is a blend of rugged mechanics and practical engineering, optimized for truck bodies rather than trailers. Here’s a detailed breakdown:
1. Engine: Yanmar TK370
The MD-200 is powered by the Yanmar TK370, a 3-cylinder, liquid-cooled diesel engine with a displacement of 1.0 liter, producing around 17-19 horsepower at 2,200 RPM. Smaller than the SB-230’s TK486V, it’s tailored for medium-duty trucks, balancing power with fuel efficiency—consumption averages 0.5-1 gallon per hour. The TK370 meets Interim Tier 4 emissions via electronic fuel injection, reducing particulates and NOx. It’s mounted low in the unit for stability, driving the compressor directly to eliminate belt wear in that linkage, though belts still power fans and the alternator.Buy Thermo King MD-200 Online
The fuel tank, typically 15-30 gallons (depending on truck integration), supports 15-30 hours of runtime, ideal for daily routes. For sustainability, the MD-200 50 variant adds electric standby, using a 230V/3-phase or 460V/3-phase motor (10-15 hp) to run off grid power when parked, slashing fuel use and noise.
2. Compressor: Thermo King X214
Cooling relies on the Thermo King X214, a 2-cylinder reciprocating compressor with a displacement of 13.92 cubic inches. It’s less advanced than the SB-230’s X430 scroll compressor but robust and serviceable, compressing R-404A refrigerant for effective heat transfer. The X214 is belt-driven on electric standby models, switching seamlessly between diesel and grid power. It’s paired with a condenser (front-mounted) and evaporator (inside the truck box), delivering consistent cooling across smaller cargo spaces.Buy Thermo King MD-200 Online
R-404A, while efficient, has a high GWP (3,922), and by 2025, it’s under phase-out pressure from regulations like the EU F-Gas rules. Operators may need to retrofit or replace it with HFC alternatives (e.g., R-452A) in the future, though the MD-200’s design supports such transitions with minimal rework.
3. Refrigeration System
The MD-200’s refrigeration circuit includes a condenser coil, evaporator coil, and a thermostatic expansion valve (TXV) for precise refrigerant control—lacking the SB-230’s Electronic Throttling Valve but still effective. The evaporator, mounted in the truck box, uses fans to circulate ~1,500-2,000 CFM of air, ample for boxes up to 20 feet. A hot-gas defrost system clears ice from the evaporator, triggered manually or via the controller, ensuring uninterrupted cooling in subzero conditions.Buy Thermo King MD-200 Online
Cooling capacity varies: ~10,000 BTU/hr at 35°F setpoint (100°F ambient) and ~6,000 BTU/hr at 0°F, with heating at ~5,000-6,000 BTU/hr. These figures suit medium-duty loads—less than the SB-230’s trailer-scale output but perfect for smaller trucks.
4. Controller: Thermoguard (Upgraded Options)
Early MD-200 units featured the Thermoguard μP-VI microprocessor, a simple digital controller for temperature settings, diagnostics, and alarms. Later models may include the SR-2 or SR-3 (retrofits or regional variants), adding touchscreen interfaces and features like OptiSet Plus for pre-programmed cargo profiles. The controller monitors sensors (return air, discharge air, coolant temp) and logs data for maintenance—ServiceWatch on newer setups tracks hours and faults.
The interface is cab-mounted or unit-mounted, with basic keys (on/off, temp set, defrost) and an alarm icon for quick alerts. Optional telematics (e.g., TracKing) connect it to fleet systems, a modern upgrade for older units.
5. Exterior and Structural Design
The MD-200’s housing is a compact, composite shell—fiberglass reinforced with resin—resistant to corrosion and UV damage. It’s smaller than the SB-230: ~60 inches wide, 24 inches deep, and 30 inches tall, weighing 800-1,000 pounds (depending on standby). The front grille aids ventilation, while side panels open for service access. It mounts to the truck’s front wall or under the chassis (undermount options), with vibration dampeners to handle road stress.
The evaporator box, inside the cargo area, is aluminum for durability, with ducting options for airflow customization. The design prioritizes compactness and ease of integration into trucks like Hino, Isuzu, or Freightliner models.Buy Thermo King MD-200 Online
6. Electric Standby (MD-200 50)
The MD-200 50’s standout feature is its electric standby, using a 3-phase motor to drive the compressor when plugged in (230V or 460V). It’s quieter (~55-60 dB(A) vs. 65-70 dB(A) on diesel) and eliminates fuel burn at depots, aligning with anti-idling laws in places like California. Automatic phase correction ensures compatibility with varying power supplies, a practical touch for diverse regions.
7. Additional Features
•CYCLE-SENTRY: Stops the engine when cooling isn’t needed, restarting for refrigeration or battery charge, saving up to 50% on fuel in light-duty cycles.
•EMI-2000: Extends maintenance intervals to 2,000 hours with premium filters and oil, cutting costs.
•Fuses and Protection: Relay board fuses (e.g., 10A, 15A) safeguard electricals, with a 12V 23-amp alternator for battery charging.Buy Thermo King MD-200 Online
Design Philosophy
The MD-200 embodies Thermo King’s focus on reliability over revolution. Its direct-drive diesel system, simple controls, and optional standby cater to operators needing a no-fuss unit for medium-duty work. It’s not as tech-heavy as newer electric models, but its mechanical simplicity and serviceability keep it humming in 2025 fleets.
Performance Specifications, Operational Modes, and Efficiency of the Thermo King MD-200
Performance Specifications
The Thermo King MD-200 is engineered to deliver reliable temperature control for medium-duty refrigerated trucks, balancing power with efficiency for boxes typically 12 to 20 feet long. Its performance hinges on its cooling and heating capacities, airflow, and operational flexibility, tailored to smaller loads than trailer units like the SB-230. Here’s a detailed breakdown based on typical Thermo King specs and industry standards as of February 23, 2025.Buy Thermo King MD-200 Online
Cooling Capacity
The MD-200’s cooling power is driven by its X214 compressor and R-404A refrigerant, optimized for medium-duty applications. Capacity varies by setpoint (desired box temperature), ambient conditions, and power source (diesel or electric standby). Thermo King rates it under standard ASHRAE conditions (American Society of Heating, Refrigerating and Air-Conditioning Engineers), with figures like these:
•High Speed Diesel (MD-200 30):
•At 35°F setpoint (2°C), 100°F ambient (38°C): ~10,000 BTU/hr (2,930 watts)
•At 0°F setpoint (-18°C), 100°F ambient: ~6,000 BTU/hr (1,758 watts)
•At -20°F setpoint (-29°C), 100°F ambient: ~4,500 BTU/hr (1,319 watts)
•Electric Standby (MD-200 50):
•At 35°F setpoint, 100°F ambient: ~9,500-10,500 BTU/hr (slightly higher with optional high-output motor)
•At 0°F setpoint, 100°F ambient: ~5,800-6,200 BTU/hr
•At -20°F setpoint, 100°F ambient: ~4,300-4,700 BTU/hr
Buy Thermo King MD-200 Online
These numbers reflect the unit’s ability to handle fresh produce (35°F), frozen goods (0°F), or deep-frozen items (-20°F). The slight dip on electric standby versus diesel is typical, as the electric motor (10-15 hp) has marginally less peak power than the Yanmar TK370’s 19 hp. Cooling capacity drops in hotter ambients (e.g., 120°F) or rises in cooler ones (e.g., 70°F), but the MD-200 maintains stability thanks to its thermostatic expansion valve (TXV), which adjusts refrigerant flow to match demand.Buy Thermo King MD-200 Online
Heating Capacity
For protecting cargo in cold climates, the MD-200 offers heating via hot gas diverted from the compressor—a standard TRU technique. Heating capacity is lower than cooling, as it’s designed for frost prevention rather than high-heat applications:
•Diesel Operation: ~5,000-6,000 BTU/hr (1,465-1,758 watts) at 0°F ambient
•Electric Standby: ~4,800-5,500 BTU/hr
This suffices for maintaining 35°F-40°F in winter, ideal for fresh flowers or vegetables. It’s not a powerhouse heater—units like the SB-230 double this—but it’s adequate for the MD-200’s medium-duty scope.
Airflow
Air circulation is critical for uniform temperatures, and the MD-200’s evaporator fans deliver ~1,500-2,000 cubic feet per minute (CFM), depending on configuration (standard vs. high-velocity options). This is lower than the SB-230’s 3,500 CFM, reflecting the smaller cargo space. At 1,500 CFM, air velocity ensures coverage for a 16-foot box, preventing hot spots or frost buildup. Operators can add ducting or baffles for custom airflow, a common tweak for sensitive loads like pharmaceuticals.Buy Thermo King MD-200 Online
Fuel Consumption
The Yanmar TK370 engine consumes 0.5-1 gallon per hour on diesel, varying by mode:
•Continuous Run: ~0.8-1 gph at full load (e.g., cooling to 0°F in 100°F ambient)
•CYCLE-SENTRY: ~0.5-0.7 gph, as the engine stops when setpoint is reached
A 15-gallon tank (common on truck-mounted units) yields 15-30 hours of runtime; a 30-gallon upgrade doubles that. Electric standby eliminates fuel use when plugged in, drawing ~7-10 kW from the grid, depending on load and motor size.Buy Thermo King MD-200 Online
Noise Levels
Noise is a practical concern, especially in urban areas. The MD-200 clocks in at:
•Diesel Mode: 65-70 dB(A) at 7 meters (high speed), dropping to 60-65 dB(A) on low speed
•Electric Standby: 55-60 dB(A), quieter due to no engine rumble
An optional acoustic package (sound-deadening foam, mufflers) shaves 3-5 dB(A) off diesel operation, meeting noise regs in places like California or Europe. It’s louder than modern electric units (e.g., E-200 at ~50 dB(A)) but typical for diesel TRUs.Buy Thermo King MD-200 Online
Operational Modes
The MD-200’s versatility comes from its operational modes, controlled via the Thermoguard (or upgraded SR-2/SR-3) interface. These modes optimize performance, efficiency, and cargo protection:
1.Continuous Run:
•Engine runs non-stop, maintaining tight temperature control (±1°F from setpoint).
•Best for high-value or sensitive loads (e.g., drugs, ice cream) where fluctuations matter.
•Higher fuel use (~1 gph) but ensures maximum cooling/heating output.
2.CYCLE-SENTRY:
•Engine cycles on/off based on temperature demand—stops when setpoint is reached, restarts if box temp drifts ±3°F or battery needs charging.
•Cuts fuel use by 30-50% in lighter loads or stable ambients (e.g., 0.5 gph in mild weather).
•Ideal for fresh produce or less critical cargo; slight temp swings are tolerable.
3.Electric Standby (MD-200 50):
•Switches to grid power (230V/460V) when parked, using an electric motor to drive the compressor.
•Zero fuel burn, lower noise, and reduced emissions—perfect for docks or depots.
•Automatic phase correction adapts to power supply quirks, ensuring reliability.
4.Defrost Mode:
•Hot gas from the compressor melts evaporator ice, triggered manually (driver input) or automatically (timer or frost sensor).
•Runs 10-20 minutes, critical for subzero setpoints to maintain airflow and efficiency.
The controller lets drivers toggle modes easily, with alarms (e.g., high pressure, low battery) flashing if issues arise. OptiSet Plus (on newer controls) pre-programs settings—say, 35°F continuous for dairy—reducing human error.Buy Thermo King MD-200 Online
Efficiency and Optimization
Efficiency is where the MD-200 shines for its class, blending mechanical simplicity with smart features:
•CYCLE-SENTRY Savings: By stopping the engine during low-demand periods, it slashes fuel costs—e.g., a 10-hour run drops from 8-10 gallons (continuous) to 5-7 gallons. In a year of daily use, that’s hundreds of gallons saved, offsetting the unit’s $8,000-$15,000 price over time.
•Electric Standby Advantage: At $0.12/kWh (U.S. average), a 10-hour standby run costs ~$8-12 in electricity vs. $30-40 in diesel (at $4/gal). In high-idle zones like California, it’s a no-brainer—plus, it complies with CARB (California Air Resources Board) idling limits.
•Thermostatic Expansion Valve: Unlike basic capillary tubes, the TXV adjusts refrigerant flow dynamically, boosting efficiency by 5-10% over older designs. It prevents overcooling, saving energy in mild conditions.
•Engine Design: The TK370’s electronic fuel injection optimizes combustion, meeting Interim Tier 4 emissions while keeping fuel burn low. It’s not as clean as Tier 4 Final engines in newer units, but retrofits (e.g., particulate filters) can extend compliance.
•Insulation Pairing: Efficiency hinges on truck insulation—Thermo King recommends 3-4 inches of polyurethane foam (R-value 20-25) to minimize heat gain, maximizing the MD-200’s output.
Drawbacks? R-404A’s high GWP (3,922) is a long-term issue—newer units use R-452A (GWP 2,140)—and diesel reliance lags behind full-electric trends. Still, for 2025 operators, the MD-200’s efficiency suits medium-duty budgets.
Performance in Context
Compared to the SB-230 (23,000 BTU/hr cooling), the MD-200’s 10,000 BTU/hr reflects its smaller scale—perfect for a 16-foot truck hauling 5-10 tons, not a 53-foot trailer with 20+ tons. Against Carrier’s Supra 660 (~11,000 BTU/hr), it’s competitive, though the Supra edges out in noise reduction. The MD-200’s strength is its Thermo King pedigree—reliable output, dealer support, and parts availability keep it humming where flashier units might falter.Buy Thermo King MD-200 Online
Reviews
There are no reviews yet.