Hello, this is Jang Gang-sim from 4050. In this session, we will look at the energy management technician written exam questions, starting from question 31 of the third session in 2016. Question 31 states: A boiler that can obtain high temperatures even at low pressure using a low substance like mercury. For question 31, you can refer to page 54 of the textbook. In this question, the first part mentions a low substance like mercury. Mercury is a special heat transfer medium, so the answer is option 2: heat transfer boiler. This special heat transfer medium can also be referred to in various ways, such as mercury down or oil. Therefore, since the question mentions mercury down, the answer to question 31 is option 2. Now, moving on to question 32: Which of the following statements about gravitational potential energy is incorrect? What is the important news?

It operates by means of gravity without using a pump, relying on the difference in density of hot water. Therefore, the lighter density of the warm water will cause it to rise, while the cooled water, after releasing heat, will have a higher density and thus will be heavier. This natural process allows the circulation of water due to gravity. In this explanation, the statement that hot water circulates due to differences in density is correct. 

Next, this method is commonly used in small-scale housing. Currently, due to the use of forced circulation pumps, it is said to be applied in large-scale systems. 

As for point three, the boiler should be installed lower than the lowest heat exchanger. This is correct; the boiler needs to be placed at a lower point so that the water can naturally flow down due to gravity. Thus, points one, two, and three are all correct. 

In point four, it states that natural circulation creates a smaller area.

It is stated that it is allowed, but in the case of natural circulation, how is the circulation? Since the circulation here is weaker than that of forced circulation using a pump, we need to make the area larger to promote circulation. So, the mistake in question 30 is number 4. Since it is a natural circulation system, the area should be enlarged to facilitate circulation. Now, let's move on to the next question.

Now, for question 33, it asks whether the size of the feed water valve for a boiler with a surface area of 12 m² must be larger than the nominal diameter. For question 33, you can refer to the content on page 6 of the textbook. It is also well explained on the right side. In the case of the feed water valve, what is the standard? In the end, the standard is that it must be larger than the nominal diameter, meaning it should be at least 15A if the surface area is less than 10 m².

되고요, 그리고 전혀 면적이 20미터보다 크게 되면 20 이상으로 하게 된다는 소리예요. 자, 그래서 33번에서 전혀 면적이 12m²라고 했죠. 자, 그래서 전혀 문제 12m² 같으면 어디에 속해? 10m보다 크잖아요. 그래서 20 이상으로 할 수 있다는 겁니다. 그러므로 33번의 답은 2번이 되겠네요. 자, 그럼 34번 문제, 극수 중 불순물에 의한 장애나 처리 방법에 대한 설명으로 틀린 것은 이라고 했네요. 자, 1번, 현탁 고형물의 처리 방법에는 침강 분리와 음집 침전 등이 있다라고 되어 있네요. 그래서 요거 우리 앞에서 배웠습니다. 현탁 고형물의 처리 방법은 뭐라고 했죠? 여기 심금 이렇게 외우라고 했잖아요. 그래서 현탁 고형물을 처리하기 위해서는 여과법과 침전법을 사용한다. 그래서 1번은 맞네요. 저희 2번 보겠습니다. 경도 정부는 이온 교환으로 연화시킨다라고.

경도 정분이 뭐냐면, 주로 칼슘, 마그네슘 같은 성분을 말합니다. 그리고 칼슘과 마그네슘 성분이 많으면 스케일이나 슬러지가 많이 발생하게 됩니다. 이런 것을 고형물이라고 부르죠. 그래서 고형물 같은 경우는 우리가 어떻게 처리를 했는지, 이 약으로 어떤 방법들로 처리를 했다고 했죠. 그래서 증류법, 이온교환법, 약품 청각법이 있습니다. 그렇다면 맞죠? 이게 경도 성분이니까 경도 성분은 이온교환으로 연화시킨다, 이온교환법이 많네요. 그래서 1번, 2번 다 맞고요. 3번을 보시면, 유지가 거품의 원인이 되나 이온교환 수지의 능력을 향상시킨다라고 되어있는데, 유지가 많으면 거품도 많이 생기고, 그리고 이온교환 수지의 능력을 저하시키게 됩니다. 그래서 처리가 잘 안 됩니다.

Therefore, the incorrect answer is number 3. Number 4 is correct. Dissolved oxygen causes corrosion in water supply systems and is accompanied by a number of factors. So, when there is a lot of oxygen dissolved, it leads to an increase in corrosion. Therefore, as the situation worsens, it results in corrosion. Thus, for question 34, the incorrect answer is number 3. 

For question 35, regarding the types of gland packing, the option that does not correspond is related to synthetic resin packing. Please refer to the explanation in question 5 for more details. If you look at the explanation, gland packing is used to maintain the sealing of valve rotating parts, and the types include braided packing, plastic packing, and metal packing. Therefore, for question 35, the option that does not correspond to gland packing is synthetic resin packing. Synthetic resin packing belongs to the category of non-drinking packing. Thus, the incorrect answer for question 35 is number...

Next, let's look at question 36. The joints used for connections in pipes, valves, pumps, and heat exchangers, which require disassembly and assembly, are called flanges. So, in this case, since there is no union, the answer will be option 3, which is flange. Now, let's move on to the next question. 

Next, question 37 asks which statement correctly explains the relationship between thermal conductivity and temperature. The first option states that as the temperature decreases, thermal conductivity increases. However, a decrease in temperature means that the temperature difference has also decreased. Therefore, when the temperature difference is low, thermal conductivity decreases. So, option 1 is incorrect. 

The next option states that as the temperature increases, thermal conductivity decreases. This implies that the temperature difference has increased. Thus, as the temperature difference increases, thermal conductivity will also increase.

So, the answer to question 3 is that as the temperature increases, the thermal conductivity increases. Therefore, option 3 is correct. In contrast, option 4 states that thermal conductivity remains constant regardless of temperature, which is nonsensical. So, the answer to question 37 is option 3.

Next, for question 38, it states that the valve that needs to be installed at a high position in heating equipment pipes or radiators is called an air vent. This refers to the air vent that is installed at the highest point of a radiator or a boiler. By installing the air vent, it helps to eliminate any trapped air in the pipes, ensuring even circulation inside. The air vent can also be referred to as an air bleeder. Thus, the answer to question 38 is option 1.

Now, moving on to question 39, it states that compared to other materials, the insulation effect is lower, and the material used for pipes, tanks, or walls at temperatures below 500 degrees Celsius is...

The content of question 39 comes from the Evo page in the textbook. Therefore, compared to other bonds, it did not have insulation effects. It is said that the protective agent used for pipes, tanks, and walls below 500 degrees Celsius is quite good. So, the answer to question 39 would be option 1. Now, let's look at question 40. It states, What are the components used to block the ends of pipes? There are two main types of components used for this purpose: caps and plugs. To explain caps first, a cap is something that covers the end of a pipe. For example, if we consider a steel pipe, the cap is used to seal the end of the steel pipe. You would tighten it with a screw to close it off. This is referred to as a cap. The cap itself has a female thread form, but it is used on a male-threaded pipe.

It indicates that it is a female connection, and the component next to that explanation, called a plug, would be the opposite. So, there is a socket like Love Me, which has a socket, one side connected to a steel pipe, and the other side is where you want to connect. Then, you would screw the plug onto it. This component, called a plug, is in a circular form, but where is it used? It is used when blocking the end of a female threaded pipe. So, it has been marked as a female connection. Now, for question 40, the component used to block the end of a 100-won pipe is a plug, but there is no plus sign, so the answer for question 40 is number 4, which is a cap. Now, let’s look at question 11. It states that a certain iron steam boiler has a maximum operating pressure of 0.3 megapascals, and we are asked about the hydraulic test pressure.

You can refer to page 57 of the textbook for this case, and you should also check the right-hand side. If we look at item 5, concerning the pressure test for steel boilers, we see a circle indicating that the maximum allowable pressure of the boiler should be below 0.43 megapascals. It states that the maximum allowable pressure should be doubled. In question 41, the maximum allowable pressure is stated as 0.35 megapascals for a boiler, which means it falls under the first item of the circle. Since 0.43 is not exceeded, doubling it gives us a value of 0.7 megapascals for the pressure test. Therefore, the answer to question 41 is option 3.

Next, let's move on to question 42. It states that something is not installed in a closed expansion tank for hot water heating systems. For question 42, you can refer to page 82 of the textbook.

You need to take note of this. Therefore, what is not installed in a sealed expansion tank is the number three exhaust pipe. The two exhaust pipes are also referred to as the through pipe. The method used here is the 102 system. So, the answer to number 42 will be three. Now, regarding question 43 about the oil boiler, the phenomenon of flickering or flashing during combustion refers to the flame flickering. We often refer to this as a flashing signal, similar to a traffic light that blinks. This means that the flame is not continuously burning; rather, it exhibits a popping or bouncing phenomenon. So, in cases where such flickering or unstable combustion occurs, it states that the cause that is least related is... Well, when the oil has a high viscosity. If the oil is too thick, it won't spray properly, which can cause buffering issues. This is quite common. Then, when moisture mixes into the oil, right?

When moisture is mixed in, it doesn't properly result in the desired combustion. So, there's a rebound effect. Then, when the fuel supply condition is unstable, it creates noise. Therefore, phenomena of total failure can occur in cases 1, 2, and 3. However, in case 4, it states that combustion occurs in a low-load state. If the boiler is in this state, there is a combustion chamber and a flue gas path. To create a load, what needs to be done is to use a blower located at the back of the combustion chamber to suck in air. What do we call this? It is referred to as induced draft or suction ventilation. In this case, the induced draft is fundamentally less powerful than forced ventilation, but it is better than natural ventilation. Therefore, it is not bad at all.

Since it is a venting system, the burner is installed this way to ensure that the air needed for combustion is efficiently drawn in. Therefore, in a stable state, air is supplied consistently, and I believe that no anomalies can occur. Thus, we can conclude that stable combustion is achieved. Consequently, for question 43, the answer that is farthest from the truth would be number 4. 

Now, let's look at question 44. The incorrect statement regarding the construction of vacuum heating piping is that, according to number 4, the use of lift fittings should be maximized, and it states that they should be within 2.5 meters. However, having more lift fittings is not necessarily better. While it does help maintain the vacuum pressure to some extent, too many fittings can create issues. Therefore, it is better to keep the distance as short as possible, and the height should be 1.5 meters.

It is correct to do it this way. We have already mentioned the height more frequently before. So, for number 44, the incorrect answer is number 4, and numbers 1, 2, and 3 are correct, so please read them individually. Now, let's move on to the next topic. 

The problem number 45 states that we want to design a steam heating system for a theater with a ceiling height of 12 meters. The average temperature for heating calculation is given as the indoor temperature at a height of 1.5 meters, which is 18 degrees Celsius. Please refer to the fourth formula for this. 

So, when the ceiling height is more than 3 meters, the average temperature (Tm) is given by the formula T plus 0.055 times (H - 3). Here, T refers to the indoor temperature at a height of 1.5 meters. I will leave it as is, with T being 18 degrees Celsius.

Plus 0.055, this will also be multiplied by 18, resulting in a height denoted by h, which will be in cubic meters per cubic meter. If we calculate this, the answer will be 26.1. Therefore, the answer for question 45 is option 2. 

Now, for question 46, it asks what percentage the steam generation efficiency of a steel steam boiler should be above. For question 46, you can refer to page 90 of the textbook, where it clearly states that the efficiency x of a steel steam boiler should be 0.98 or higher, while the efficiency of a cast iron steam boiler should be at least 0.6. This means that when converted to a percentage, 0.98 translates to 98%, and the other value can be rounded to 60%. Thus, for question 46 regarding the steel steam boiler, the answer would be 98%.

So, it needs to be over 98%. Therefore, the answer to question 46 would be 4. Now, looking at question 47, it asks which of the causes of boiler accidents is not due to boiler handling. In Japan, it mentions material and design flaws, but material and design issues fall under the manufacturer's responsibility. So, the incorrect option is 1. The rest, such as operating under excessive pressure, indicates that the operator did not properly monitor the pressure, which is a handling issue. Then, option 3 regarding improper level monitoring is also a handling issue. Similarly, option 4, which mentions poor water supply management, is also a cause related to the operator's handling. Therefore, for question 47, the cause that is not related to handling is option 1. 

Moving on to question 48, it asks which of the following is not included due to boiler corrosion. The answer is option 4, which is related to study conditions. It's simple; you just need to remember that corrosion can occur due to high-temperature conditions.

There is corrosion advice, so as long as the kids know about it, there shouldn't be any major issues. For question 48, it states, Which of the following is not internal corrosion? Therefore, option 4, high-temperature corrosion, is considered external corrosion. Now, let's move on to the next one. 

Next, for question 49, it asks about the characteristics of boiler steel plates in relation to the properties of alkaline and high-pressure environments, and which explanation is incorrect. If you look at the explanation on the right, it mentions that in high-temperature, high-pressure boilers, the boiler water tends to be highly alkaline. As a result, corrosion occurs primarily at the bottom surface that comes into contact with the highly alkaline water, and it mainly occurs in the lower parts. It does not happen in welded boilers. 

So, returning to the characteristics of alkaline and high-pressure phenomena, the question asks which explanation is incorrect. In high-pressure boilers, if the concentration of alkaline substances in the boiler water is high, corrosion is likely to occur. There are many such cases in Japan.

The occurrence is likely to happen between the upper surface of the water and the ribs, but it was just read incorrectly. It should be that it occurs between the lower surface and the management area. So, the mistake is that it’s not the upper surface but the lower one. The remaining points three and four are correct, so please read them once. 

I have a heating load of 2002 and 150 kcal power, and it states that the surface area of the hot water heater is to be set to the standard direction. So, the heating load formula is represented as small q multiplied by A. Therefore, the heating load in the room is based on the area. Since it is stated per area, it works that way. 

However, in this problem, since it specifies that the direction of the interference is to be set to the standard direction, these should be adjusted accordingly. This means that it changes to the standard direction, and this will also alter the surface area of the heating. So, if we write the formula again, it will be q.

It is easy to change the small size and the destruction into BR. There is nothing difficult about it. The official age of Lee Hong-sik or that guy is given. So, I will set the given conditions: the southern region is 2250, so the table is 2250, and since 20Q is the standard direction, the water boiler is 5. Then, here it would be 452. And the destruction idea is that the standard area is to find DR. So, 2 BIE 450 goes down to 4 or 2250. Therefore, it needs calorie per, and it becomes Kcal per m. So, it goes up to Kcal power recording, and it rises to m. Thus, the heat transfer area at this time would be 5m. Therefore, the answer to question 50 will be option 3. Now, for question 51, the steam trap is a mechanical temperature control type thermodynamic trap. When divided into nine, the temperature control trap corresponds to the setting sun, and the temperature control trap is also referred to as a 10-moving trap.

The answer to question 1 is 3. For question 52, regarding measures to prevent overheating of the boiler, the incorrect option is as follows: 

1. Remove scale and foreign substances from the boiler. This is correct; removing scale and impurities can help prevent overheating. 

Next, to prevent the concentration of the boiler due to a large amount of impurities, this is also correct. As a result of concentration, sludge is generated, and if circulation is not functioning properly, overheating will occur. 

Now, for option 3, it states that the boiler's water level should not fall below the safe level. This is correct; if it falls below the safe level, it will lead to internal overheating. Therefore, it is essential to maintain the water level properly to prevent this from happening. 

Thus, options 1, 2, and 3 are all correct measures to prevent overheating. However, in option 4, it states that the flame should be concentrated locally. If heat is concentrated in one specific area, it will undoubtedly lead to overheating and an accident. 

Therefore, the incorrect option this time is 4.

Next, let's move on to question 53. It states the precautions to take when discharging steam generated from a boiler, and we're looking for the incorrect one. Discharging steam from the boiler means sending it to the rear side. At this time, the precautions are as follows: 

1. Discharge the condensate from the steam line. That's correct because it prevents water hammer. So this one is right. 

2. If the pressure is too high, it can cause a sudden change in the internal conditions, which could lead to phenomena like water hammer. So, this one is also correct. 

3. After discharging, be mindful of pressure fluctuations in the steam pressure. That's obvious, so this is correct as well. 

Now, the incorrect one is number 4, which states to check for any abnormalities in the opening and closing status of the valve after discharging and to leave the drain valve open. However, if you leave the drain valve open, all the water inside will drain out.

If done incorrectly, it can lead to more than just a problem with the assistant. Therefore, the incorrect answer is number 4. After the installation, it is correct to check for any abnormalities in the valve's opening and closing status. So, how is this map installed? Therefore, the incorrect answer for question 53 is number 4. In question 14, regarding steam heating, if the horizontal piping becomes narrower at a certain point, the appropriate option for using an eccentric reducer would be number 4. To prevent the accumulation of condensate, as mentioned earlier, if a concentric reducer is used, what happens? If it is used this way, condensate can be visible here. Therefore, in horizontal piping, using such an eccentric reducer allows the condensate to pass through smoothly. Thus, the answer to question 54 is number 4: to prevent the accumulation of condensate, an eccentric reducer is used. In question 55, regarding the Energy Utilization Act, the articles of incorporation of the establishment organization are...

Regarding the necessary matters about the supervisor, it is not specified by anyone's decree. In the case of question 55, you can refer to page 280 of the textbook. On page 280, you will find the purpose of establishment. If you look at the purpose of establishment, it states that the necessary matters regarding the establishment of an organization and the supervisor shall be determined by presidential decree. Therefore, the answer to question 55 is option 1.

Now, for question 56, it asks which of the following is not considered a user material under the Energy Use Rationalization Act. For question 56, please refer to pages 264 and 265 of the textbook. The option that is not considered a user material is option 3, the electric instantaneous water heater.

Next, moving on to question 57, it is about the purpose of the Energy Use Rationalization Act. It states that the terms that should be filled in the blanks are as follows. For question 57, you can refer to page 238 of the textbook, which discusses the responsibilities and objectives. I will read the content within the box.

The Energy Utilization Rationalization Act aims to stabilize energy supply, promote the rational and efficient use of energy, and reduce environmental damage caused by energy consumption. By minimizing environmental harm, it contributes to the sound development of the national economy, the improvement of public welfare, and the mitigation of global warming. Therefore, the answer to question 57 is option 3. 

Now, let's look at question 58. According to the Energy Utilization Rationalization Act, what is not included in the high-efficiency energy certification target equipment? For question 58, you can refer to page 254 of the textbook. The existing equipment that is not included in the high-efficiency energy certification target is the power transformer. 

For question 59, which pertains to the support items for energy technology development projects under the Energy Act, you can refer to pages 234 and 235 of the textbook.

So, the items that do not apply are related to the existing energy cooperation, which is stated as number 9. This pertains to international cooperation, not domestic. Therefore, the mistake in question 59 is noted. Now, let's move on. 

Next, for question 60, according to the Energy Utilization Rationalization Act, the penalty for using inspection-target equipment that has not passed inspection is a frequent topic. You can find this on page 286. In cases where equipment that has not passed inspection is used, the penalty is imprisonment for up to one year or a fine of up to 10 million won. Thus, the answer to question 60 is option 2.

With this, we have completed all the material for the Energy Management Technician written exam, including the theoretical part and previous questions. Of course, there are health-related questions in the D section, but the CBT questions are just a mix of previously covered topics, selected from those that were well-presented.

Since everything has been resolved, there shouldn't be any major difficulties for you all. Of course, if you have any doubts about the theory or are unsure, please feel free to post your questions in the café, and I will do my best to answer them sincerely. Now, for those of you preparing for the written exam, I appreciate all the hard work you've put into following the theory lessons. Once again, I want to emphasize that if you follow my theory lessons in order and review all the past exam questions, I can assure you that passing the exam shouldn't be a major issue. 

Please make sure to wrap up your preparations well, and I hope everyone passes the written exam. I look forward to seeing you in the practical lecture later on. Thank you all for your hard work, and I wish everyone the best of luck in passing. You've all done a great job!

에너지관리기능사 필기 기출문제 풀이 2016년 제3회 (31~60번)

에너지관리기능사 필기 기출문제 풀이 2016년 제3회 (31~60번)