What is the relationship between cooling water temperature T and condenser pressure P
What is the pressure in the steam condenser Mcq?
Explanation: Steam condensers maintain very low back pressure at the exhaust side of the piston of a steam engine (or a turbine). This improves the quality of expansion of steam, steam expands to a greater extent and turbine efficiency is increased. Explanation: Sub-atmospheric pressure is vacuum pressure.
What is the effect of the increase in the superheat at constant pressure and condenser pressure on mean temperature of heat addition?
What is the effect of the increase in the superheat at constant pressure? Explanation: As there is an increase in superheat at constant pressure, the cycle efficiency increases & hence there is an increase in the mean temperature of heat addition. 5.
What is the effect of increasing temperature of heat addition by superheating?
The average temperature at which heat is added to the steam can be increased without increasing the boiler pressure by superheating the steam to high temperatures. Superheating the steam to higher temperatures has another very desirable effect: It decreases the moisture content of the steam at the turbine exit.
What is the relation between cooling water temperature?
In practice, the temperature difference between cooling water and steam is about 10°C to 15°C. For example, if the cooling water is at 20°C, the condenser temperature is about 35°C and corresponding saturation pressure is 0.006 MPa. The corresponding thermal efficiency of the cycle would be 32% (refer to Figure 3.).
Related guide for What Is The Relationship Between Cooling Water Temperature T And Condenser Pressure P ?
What is the cooling temperature of water?
For cooling water (16°C to 30°C), cooling towers are widely used and offer good opportunities for energy saving through low-cost actions such as VSDs for fan control. The total cost of cooling when using cooling towers is often increased substantially because of the need for Legionella controls.
What is the condenser pressure?
The lowest feasible condenser pressure is the saturation pressure corresponding to the ambient temperature (i.e. absolute pressure of 0.008 MPa, which corresponds to 41.5°C). The goal of maintaining the lowest practical turbine exhaust pressure is a primary reason for including the condenser in a thermal power plant.
Is condenser pressure lower than atmospheric pressure?
Most of condensers in power plant operates below atmospheric pressure.
In which type condenser water and steam do not mix directly Mcq?
Surface condensers: In these types of condensers shell-and-tube type heat exchangers are used where two fluids do not come in direct contact and the heat released by the condensation of steam is transferred through the walls of the tubes into the cooling water continuously circulating inside them.
Why should the reheat pressure be Optimised?
A high reheat pressure increases the the moisture content at turbine exhaust which results in scaling and it should be optimised. Thus the work produced is increased ,thereby efficiency increases.
How do boiler and condenser pressures affects the thermal efficiency of a vapor power cycle?
Increasing the Boiler Pressure (Increase TH)
Increasing the operating pressure of the boiler leads to an increase in the temperature at which heat is transferred to the steam and thus raises the efficiency of the cycle.
What are the advantages of reheat cycle?
Advantages: The advantages of using a reheat cycle are higher thermal efficiency, reduced feed water pump power, smaller condenser, smaller boiler, long life of the turbine and less handling of the fuel and firing requirement.
How does superheating increase efficiency?
As for the Carnot cycle, the thermal efficiency tends to increase as the average temperature at which energy is added by heat transfer increases. Superheater – increases the steam temperature above the saturation temperature. Reheater – removes the moisture and increases steam temperature after a partial expansion.
Why does superheat increase efficiency?
Heat regeneration increases the thermal efficiency, since more of the heat flow into the cycle occurs at higher temperature. Heat regeneration causes a decrease in the mass flow rate through low-pressure stage of the steam turbine, thus increases LP Isentropic Turbine Efficiency.
How do you increase mean temperature of heat addition?
Mean temperature of heat addition can be increased by? Explanation: Increasing condensor pressure decreases turbine exit temperature which in turn increases mean temperature of heat addition. 3.
Is the relation between cooling water and condenser pressure?
The results of this study indicate that the increase in cooling water temperature causes the heat transfer rate and the pressure inside the condenser to get higher. Conversely, the greater flow rate causes the heat transfer rate and condenser pressure to decrease.
What is the effect of increasing water flow rate to cooling load?
This means that the cooling capacity increases and power in put decreases with increasing water mass flow rate which results in higher COP of the air conditioning cycle as shown in Fig. 6.
What is cooling water system?
The function of a cooling system is to remove heat from processes or equipment. Heat removed from one medium is transferred to another medium, or process fluid. Most often, the cooling medium is water. Many of the properties of water, along with the behavior of the contaminants it contains, are affected by temperature.
Why water based cooling systems increase the working pressure in the system?
The cooling system is pressurized to increase the boiling point of the coolant. When the system is hot, removing the pressure cap could cause the system's cooling system to boiling point.
Why is thermostat used in water-cooling system Mcq?
The thermostat helps to bring the cold engine to the operating temperature quickly. It is fitted between the water outlet of the cylinder head and the inlet of the radiator in the water-cooling system.
How do you calculate cooling water requirements?
Subtract the water's temperature as it leaves the chiller, measured in degrees Fahrenheit, from its temperature on entering it. For example, if water enters the chiller at 40 degrees Fahrenheit and leaves at 66 degrees Fahrenheit: 66 - 40 = 26 degrees.
How the condenser pressure is determined?
The condenser pressure is dictated by two factors, either of which may be limiting: The condenser performance, which is a function of the thermal duty (amount of steam that must be condensed) and the cooling water flow rate and temperature. The NCG removal system capacity.
Does a condenser increase pressure?
Evaporating temperature and evaporating pressure increase as the pressure drop increases. The enthalpy difference across condenser and compressor, however, increase with the increasing pressure drop.
What causes high condenser pressure?
One common cause of high discharge pressure is the cooling medium (air or water) flowing across the condenser: either there is not enough or the temperature of the cooling medium is too high. This is normally easy to identify with a simple visual inspection of the condenser.
Does a condenser reduce pressure?
Temperature profile inside the condenser
In a similar way to evaporation, the only pressure difference between the entrance and the exit of the heat exchanger is the pressure drop. Because the flow velocity in a condenser decreases, the induced pressure drop is much lower than in an evaporator.
Why is condenser pressure low?
Refrigeration and Heat-Pump Systems
The condensing pressure is generally much lower because the cooling tower performance depends on the ambient wet-bulb temperature. The net result is reduced energy costs but increased capital and maintenance costs.
What is the condensing temperature?
The condensing temperature of the compressor system usually refers to the temperature at which the refrigerant condenses in the condenser. The vapor pressure of the refrigerant corresponding to the temperature is the condensing pressure.
How water coming out of condenser is cooled in a?
The condensers are usually shell and tube heat exchangers, with refrigerant circulating through the shell and cooling water flowing through the tubes. Condenser water pumps circulate the hot condenser water to the cooling tower where it is cooled by air.
In which condenser mixing of coolant and condensation does not take place?
In surface condensers, the coolant does not contact the vapors or condensate. In contact condensers, coolant, vapors, and condensate are intimately mixed. Most surface condensers are of the tube and shell type shown in Figure 1.
What is the purpose of condenser Mcq?
Explanation: Condensers use the property of condensation which is a convective heat transfer process that is associated with a change in the phase of a fluid from the gas to a liquid phase.
What is the function of a condenser in a thermal power plant?
In thermal power plants, the purpose of a surface condenser is to condense the exhaust steam from a steam turbine to obtain maximum efficiency, and also to convert the turbine exhaust steam into pure water (referred to as steam condensate) so that it may be reused in the steam generator or boiler as boiler feed water.
What is ideal regenerative cycle?
In an ideal regenerative Rankine cycle, steam enters the turbine at the boiler pressure and expands isentropically to an intermediate pressure. Some steam is extracted at this state and routed to the feedwater heater, while the remaining steam continues to expand isentropically to the condenser pressure.
Which of the following is the relation between compression ratio?
Which of the following is the relation between compression ratio, expansion ratio and cut-off ratio? Explanation: Here rk=compression ratio, re=expansion ratio and rc=cut-off ratio. 7. The efficiency of Diesel cycle is ____ the efficiency of Otto cycle.
How do you calculate condenser efficiency?
Vacuum efficiency = (Actual vacuum in condenser X 100)/Max. Obtainable vacuum. Example-4: The air leakage into the steam condenser is 0.721 kg/min.
What is the effect of lowering the condenser pressure on pump work input?
Lowering the condenser pressure results in increasing the area of the TS diagram, hence improves the net work output of the cycle and improves the thermal efficiency of the cycle.
Where is the condenser pressure Rankine Cycle?
Why reheater is used in boiler?
— Reheater is a part of the boiler which to reheat steam output from the first level of the steam turbine. Reheated steam will again absorb the heat energy from the boiler to be used in the next level steam turbine. Reheater is one way to improve the thermal efficiency of the Rankine Cycle.
Which boiler is critical boiler?
A supercritical steam generator is a type of boiler that operates at supercritical pressure, frequently used in the production of electric power. In contrast to a subcritical boiler in which bubbles can form, a supercritical steam generator operates at pressures above the critical pressure – 22 megapascals (3,200 psi).
Why reheater is used in gas turbine?
Reheating is applied in a gas turbine in such a way that it increases the turbine work without increasing the compressor work or melting the turbine materials. When a gas turbine plant has a high pressure and low pressure turbine a reheater can be applied successfully.
What is purpose of reheat cycle Mcq?
Explanation: Reheat cycle is worked with rankine cycle to remove the moisture from the steam.
What is binary Vapour cycle?
A binary cycle (also binary vapor cycle) in thermodynamics is a power generation method that uses two circuits, high temperature one and lower temperature one.