Free Practice Questions for MMO MTST Refrigeration Installation

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Sample MMO MTST Refrigeration Installation Practice Questions

Try these sample questions to review concepts for the MMO MTST Refrigeration Installation exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 20+ question experience with AI tutoring.

1A theoretical Carnot refrigerator operates between cold and hot reservoirs at -20°C and 40°C. Using COPc = Tc/(Th-Tc), with absolute temperatures in kelvins, what refrigeration COP is obtained?

A.0.333

B.5.22

C.3.00

D.4.22

Explanation: The reservoir temperatures are 253.15 K and 313.15 K. Carnot refrigeration COP is 253.15/(313.15-253.15) = 4.22, a theoretical reversible limit rather than an actual compressor-system rating.

2A simple cycle has compressor-inlet enthalpy 400, discharge enthalpy 450 and evaporator-inlet enthalpy 250 kJ/kg. Neglect other energy transfers. What refrigeration COP follows?

A.2.0

B.3.0

C.4.0

D.8.0

Explanation: Specific refrigeration effect is 400-250 = 150 kJ/kg and compressor work is 450-400 = 50 kJ/kg. Refrigeration COP is their ratio, 150/50 = 3.0.

3What is the usual role of a liquid receiver on the high-pressure side of an appropriate refrigeration system?

A.Store liquid refrigerant and accommodate inventory changes

B.Prevent every possible liquid slug at the compressor suction

C.Replace the condenser's heat-rejection duty

D.Regulate evaporator superheat without a metering device

Explanation: A receiver provides liquid storage for the system's refrigerant inventory under its intended operating and service conditions. It is distinct from a suction accumulator and does not replace the condenser or expansion control.

4At an evaporator outlet, measured vapor temperature is -4°C and the saturation dew-point temperature at that same local pressure is -10°C. What outlet superheat is indicated?

A.14 K

B.-6 K

C.6 K

D.10 K

Explanation: Superheat is actual vapor temperature minus the saturation dew-point temperature at the measurement pressure. Here it is -4-(-10) = 6 K; acceptability depends on the equipment and control requirements.

5A suction riser is proposed for a variable-capacity compressor. Which check is most relevant to reliable oil return?

A.Checking only maximum-load pressure drop

B.Applying a single velocity value to every refrigerant and pipe geometry

C.Assuming oil always returns because the pipe slopes somewhere

D.Checking manufacturer oil-return and pressure-drop guidance across minimum and maximum operating flows

Explanation: Low-load gas flow can be critical for oil transport, while high-load flow can govern pressure drop. Appropriate riser design therefore needs the operating range and refrigerant/equipment-specific guidance.

6In ASHRAE refrigerant safety classification, what does A2L indicate?

A.Higher toxicity with no flame propagation

B.Lower toxicity with lower flammability and the specified low burning-velocity subclass

C.Lower toxicity with no flame propagation

D.Higher toxicity with high flammability

Explanation: The letter A denotes the lower-toxicity group, and 2L is the lower-flammability subclass with a specified low burning-velocity criterion. It does not mean nonflammable or remove the need for charge, ventilation and application safety checks.

7A cold-room surface has area 40 m², U-value 0.25 W/(m²·K) and temperature difference 30 K. What steady transmission load results?

A.300 W

B.30 W

C.1200 W

D.3000 W

Explanation: The load is UAΔT = 0.25 × 40 × 30 = 300 W. Other surfaces, thermal bridges and additional load sources must be assessed separately.

8A batch of 1000 kg is cooled from 10°C to its freezing point -2°C, frozen, then cooled to -18°C in 16 hours. Use cp above freezing 3.5 kJ/(kg·K), latent heat 250 kJ/kg and cp below freezing 1.8 kJ/(kg·K). Ignore packaging and other loads. What average product load results?

A.4.34 kW

B.5.07 kW

C.5.57 kW

D.20.1 kW

Explanation: Energy per kilogram is 3.5 × 12+250+1.8 × 16 = 320.8 kJ/kg. Dividing 320,800 kJ by 16 × 3600 s gives 5.57 kW, including both sensible stages and freezing.

9A cold-room infiltration estimate is 200 kg dry air/h. Incoming-air enthalpy exceeds room-air enthalpy by 45 kJ/kg dry air. What average infiltration load is estimated?

A.9.0 kW

B.0.90 kW

C.4.5 kW

D.2.5 kW

Explanation: The energy rate is 200 × 45 = 9000 kJ/h. Dividing by 3600 converts this to 2.5 kW, including the enthalpy difference's sensible and latent contributions.

10Inside a cold room, fans draw 0.4 kW for 18 h/day, lights 0.2 kW for 4 h/day and occupants contribute 0.3 kW for 2 h/day. Assume all this energy enters the room. What daily internal heat is added?

A.8.6 kWh/day

B.0.9 kWh/day

C.21.6 kWh/day

D.7.2 kWh/day

Explanation: Daily energy is 0.4 × 18+0.2 × 4+0.3 × 2 = 7.2+0.8+0.6 = 8.6 kWh. Loads with different operating schedules must be integrated separately rather than assumed continuous.

About the MMO MTST Refrigeration Installation Exam

Independent practice for MTST refrigeration-installation engineering. Study cycle behavior, equipment and refrigerant properties, followed by loads, log p-h balances, capacity selection and cold-room project judgment.

Exam sponsor: TMMOB Makina Mühendisleri Odası (MMO) / PBK. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

60-minute theory section: cycles two questions/10 points, components three/15 and refrigerants one/5. The 120-minute project section covers load 20, log p-h cycle 15, component capacity 15 and cold-room design 20 points. Pass 70/100. No separate oral or hands-on component is described on the scheme page.

Time Limit

180 minutes (60 + 120)

Passing Score

70/100

Exam / Certification Fees

Published PBK general tariff checked 21 October 2026: TRY 1,500 certificate including VAT; no additional examination fee. Course tuition separate; confirm current charges.

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

PBK MTST qualification scheme · Source checked 2026-10-21Identity, prerequisites, six theory/four project tasks, distribution, duration and pass mark. Use the general tariff for current fee information.
PBK current fee page · Source checked 2026-10-21Engineering certificate TRY 1,500 including VAT; no additional examination fee.
MMO 2026 course catalogue · Source checked 2026-10-21Current-year refrigeration qualification training listings; chosen examination booking requires provider confirmation.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

2 items (10%)

Theory: cycles

Ideal-cycle limit and vapor-compression COP.

3 items (15%)

Theory: components

Receivers, superheat and oil return.

1 item (5%)

Theory: refrigerants

Safety-class interpretation.

4 items (20%)

Project: loads

Transmission, products, infiltration and internal schedules.

3 items (15%)

Project: log p-h

Throttling, mass flow and compression.

3 items (15%)

Project: component capacities

Compressor, condenser and evaporator checks.

4 items (20%)

Project: cold-room design

Vapor control, condensation, daily duty and defrost.

Preparing for the MMO MTST Refrigeration Installation Exam

What You Need to Know

Passing score: 70/100
Assessment: 60-minute theory section: cycles two questions/10 points, components three/15 and refrigerants one/5. The 120-minute project section covers load 20, log p-h cycle 15, component capacity 15 and cold-room design 20 points. Pass 70/100. No separate oral or hands-on component is described on the scheme page.
Time limit: 180 minutes (60 + 120)
Exam / certification fees: Published PBK general tariff checked 21 October 2026: TRY 1,500 certificate including VAT; no additional examination fee. Course tuition separate; confirm current charges. Official sources

Using Our Practice Resources

Work through all 20 available questions
Review every answer and explanation
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MMO MTST Refrigeration Installation: Suggested Study Strategy

1Label each log p-h state and calculate enthalpy differences consistently.

2Separate daily heat energy from instantaneous equipment capacity.

3Use manufacturer data at actual cycle conditions and verify safety and defrost provisions.

Frequently Asked Questions

What eligibility is published?

The PBK scheme lists mechanical engineering, the mechanical-installation qualification and at least 12 hours of relevant training. Confirm current enrolment conditions with MMO.

Are official assessment languages confirmed?

No permitted response languages are established by the reviewed sources. Confirm directly with PBK; an English study bank is not evidence of an official English examination.

How does this resource support the project?

Its study proportions follow the published theory/project point split. The official work still requires written calculations and diagrams; complete full refrigeration and cold-room projects alongside these MCQs.