- •Міністерство аграрної політики україни
- •Table of Contents. (Зміст)
- •Plate Heat Exchanger. ( The main components).
- •1. Match the words from the left column with their translations in the right
- •2. Make up sentences with the key words.
- •3. Read the text and find the sentences with the key words in the text. Main components.
- •4. Discuss the questions.
- •Vocabulary.
- •A direct expansion evaporator.
- •1 Match the key words with their translations.
- •2. Write your ideas of what you would like to know about a direct expansion evaporator.
- •3. Read the text and say if you have found the answer. A direct expansion evaporator.
- •Vocabulary.
- •Flooded flow
- •Flooded flow.
- •6. Complete the sentences.
- •7. Discuss the questions
- •8. Complete the sentences with the correct form of the verbs in bra-
- •9. Translate these sentences into English.
- •Vocabulary.
- •The basic refrigeration cycle.
- •1. Match the words from the left column with their definitions in the right column.
- •2. Write your ideas of what you would like to know about the basic refrigeration cycle.
- •3. Read the text and say if you have found the answer. The basic refrigeration cycle.
- •4. Find the sentences with the key words in the text guess the meaning. Use a dictionary to check the answer.
- •5. Discuss the questions.
- •1. Read the text, find the sentences with the key words and guess the meaning. Use a dictionary to check the answer. The basic refrigeration cycle. Part 2
- •2. Read the text again. Answer these questions.
- •The expansion process and devices
- •In all types of the refrigeration cycle there is a step where liquid refrigerant is expanded from the condensing pressure to the evaporating pressure. Refrigerant evapo-
- •2. Read the text again and correct the mistakes. Begin your answer with:
- •3. Complete the sentences.
- •4. Give affirmative answers to the following questions according to the given model:
- •5. Complete the with the correct forms of the verbs given in brackets.
- •Vocabulary
- •1. Match the words from the left column with their definitions in the right colomn.
- •2. Write your ideas of what you would like to know about the pressure drop.
- •3. Read the text and say if you have found the answer. Methods to control the pressure drop
- •4. Find the key words in the text and guess the meaning. Use a dictionary to check the answer.
- •5. Discuss the question.
- •Vocabulary.
- •The compressor.
- •1. Match the words with their translation.
- •2. Read the text and answer the questions.
- •Evaporators, condensers and interchangers.
- •1. Match the Key words with their translation.
- •2. Use your knowledge and answer the questions.
- •3. Now read the text quickly and check your guesses. Evaporators, condensers and interchangers.
- •4. Read the text more carefully.
- •6. Make these sentences negative.
- •Vocabulary.
- •Literature.
- •Рецензія
2. Read the text again. Answer these questions.
1. How can the fraction evaporated be founded?
2. Where does the partly vaporized refrigerant enter?
3. What happens in the evaporator?
4. Where is the vapour compressed to the condensation pressure?
5. What kind of energy is applied to the vapour?
6. How should the vapour move?
7. Why does the vapour move along the isenthalp?
8. What happens to temperature with compression?
9. What happens quicker, the increase of the temperature or the pressure increase?
What does it give?
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3. Complete the sentences.
1. The fraction evaporated………..
2. The partly vaporized refrigerant…..
3. The vapour leaves the evaporator…….
4. Mechanical but……….
5. The vapour is……..
6. With compression……
7. The increase of the temperature……..
8. The refrigerant not……………
4. Write the questions to the sentences.
1. The intercooler between the compressors stages is not possible for a compressor with only an intermediate vapour inlet.
2. Refrigerant leaves subcooled to 35 C.
3. The entire refrigerant is flashed to an intermediate pressure and the vapour/liquid is separated in the economizer separator.
5. Fill the gaps with the necessary words.
1. The liquid has reached ______and the _______can be found from the lines for_______.
2. The refrigerant at first reaches point C,__________, but usually leaves____________.
3. The vapour is compressed to the________________ in the compressor.
6. Correct these statements.
1. The partly vaporized refrigerant does not enter the evaporator and the remaining liquid
refrigerant evaporates, producing the required heating effect.
2. The vapour is compressed to the condensation pressure in the evaporator.
3. The vapour should not move along the isentropical.
4. The temperature decreases with the compression.
7. Complete the sentences with the correct form of the verbs in brackets.
1. The vapour (to be compressed) ______to the condensation pressure in the compressor.
2. The vapour (to be compressed) _______to the condensation pressure in the compressor
now. (Present Continuous Passive.)
3. The vapour (be compressed) _______just______ to the condensation pressure in the
compressor. (Present Perfect Passive)
4. The vapour (to be compressed) _______to the condensation pressure in the compressor
in some minutes.(Future Simple Passive).
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The expansion process and devices
Key words
Refrigeration cycle, liquid refrigerant, to expand, condensing /evaporating pressure, to evaporate, to cool down, expansion device, fluid, flow length, drop.
1. Read the text, find the sentences with the key words and guess the meaning. Use a dictionary to check the answer.
The expansion process and devices.
In all types of the refrigeration cycle there is a step where liquid refrigerant is expanded from the condensing pressure to the evaporating pressure. Refrigerant evapo-
rates and simultaneously cools down to the evaporation temperature.
The expansion device could be any type of restriction which exerts a pressure drop
on the fluid which is equal to the difference between the condensation and evaporation
pressure for the actual refrigerant flow rate.
Fluid dynamic theory teaches us that the pressure drop
Increases with: Increasing flow length
surface roughness
direction changes
Decreasing hydraulic diameter
Cross-section area.
Theoretically, all these parameters could be used to control the pressure drop but it
is difficult to imagine a device, which uses the surface roughness. Similarly, the number of directional changes and the flow length closely interrelated as are the hydraulic diameter, the cross section area and the de/acceleration.