1. The most common of these are used in air-conditioning, water cooling and some industrial processes. Each stage operates on the ideal vapor-compression refrigeration cycle with refrigerant-134a as the working fluid. In Cascade refrigeration, cooling effect is produced by (a) Latent heat (b) Total heat (c) Sensible heat (d) None (Ans:a) The ratio of COP of a two stage Cascade refrigeration system vs three stage cascade system is (a) < 1 (b) > 1 (a) = 1 (d) None (Ans: a) In a 2 stage cascade refrigeration system, cooling effect occurs in the (a) one evaporator A cascade refrigeration cycle is a multi-stage thermodynamic cycle.An example two-stage process is shown at right. That controller in turn uses the actuator to apply its control effort directly to the secondary process. However, in cascade amplifier meant for providing high gain, only CE amplifier stage are connected in cascade. (d) None 4. A cascade filling system is a high pressure gas cylinder storage system which is used for the refilling of smaller compressed gas cylinders. Share 0 . c. Improve the operation of the system The corresponding values of second amplifier are : 25, 80 KΩ, 12 KΩ, 1.2 MΩ respectively. d. 1.0 to 1.0. 0.6 to 1.7 A pressure transmitter is wired directly to a VFD and a DDC Controller from a BAS system only starts and stops the VFD. Split-Range, Auto-Selector, Ratio & Cascade Systems X MCQ on Flow Measurement Multiple Choice Questions MCQ ON Flow Measurement 1.A differential pressure transmitter is calibrated 0 to 80 inches of water and transmits a 4 to 20 mA dc signal. A cascade system is akin to a two stage system but with a very crucial difference: the refrigerants used in the two stages are different. Data b. The duplex controller provides the following number of control valve signals: Save my name, email, and website in this browser for the next time I comment. c. Can be used for even-numbered ratios In cascade control system two controllers are cascaded to each other as shown in the diagram below. c. Two independent control systems are Dot economical PRECAUTIONS . Jacques: November 16, 2016 at 2:17 pm. the evaporator with the first unit cools the condenser of the second unit). TWO- AND THREE-STAGE CASCADE REFRIGERATION SYSTEM By: Paul B. Reed INTRODUCTION Mechanical refrigerating systems in most common use fall into three classes as far as the temperatures of the evaporators are concerned: 1. Which of the following is the correct connection? High temperatures, with evaporators from about 30°F to 60°F. Let us derive state space equations for the system which is linear and time invariant. b. Lengthen the period of the total system b. Can be used with any combination of related process variables In order to determine the impact of R50 on the refrigeration cycle, the experiments are made by using mixed-refrigerants with R134a/R23/R14 and R134a/R23/R14/R50 containing the same quantity of R134a, R23 and R14 respectively in the same device. Increase them Now we are taking n state variables to describe the given system hence n = x1, x2, ……….. xn. (Ans: c), In cascade refrigeration, condenser of low temperature refrigeration is coupled with A primary or master controller generates a control effort that serves as the setpoint for a secondary or slave controller. Place the primary controller on manual and adjust the secondary controller d. Valve position, 9. (c) Condenser of high temperature (b) Three stage Let us consider multiple inputs and multiple outputs system which has r inputs and m outputs. And m = y1, y2 ……….. ym. Vapor Compression refrigeration -2. Cascade Formula Interpretation Rest of LNA Front-End We see that in a cascade, the noise contribution of each successive stage is smaller and smaller. This website uses cookies to improve your experience. R32/R1234ze(E) zeotropic mixtures are chosen as … Two flows are to be ratio controlled, the first is measured with an orifice and the second with a shedding vortex flowmeter. A duplex controller has the following number of inputs: a. Shorten the period of the total system Simplified Drawing Showing Piping Arrangement of a Two-Stage Cascade System . B. frequency response of the first amplifier. (c) Four stage You should first, a. Thus, every communication system employs a low noise amplifier … b. First-stage voltage gain in db = 20 log 10 100 = 20 × 2 = 40. Is it applicable for all cascade control system scenarios? The Cascade Control Block Diagram shows a generic cascade control system with two controllers, two sensors, and one actuator acting on two processes in series. Compressor and Compression Ratio First, we need to understand the function of a compressor in a closed cycle refrigeration system. Huge collection of MCQ questions c. Online MCQ quiz d. Subjective questions and answers 90. Learn competitive MySQL mcq questions and answers with easy and logical explanations (Ans: b), For achieving -1000C temperature, cascade refrigeration used is A pinoybix mcq, quiz and reviewers. Second-stage voltage gain in db = 20 log 10 200 = 20 × 2.3 = 46. Where, r = u1, u2, u3 ……….. ur. 2. Drift b. Oscillate c. Increase amplitude …, MCQ ON Flow Measurement 1.A differential pressure transmitter is calibrated 0 to 80 inches of water and transmits a 4 to 20 mA dc signal. 39.2 Cascade Systems ..... 39.3 Low-Temperature Materials ..... 39.6 Insulation ... operate against in two-stage systems. (b) Evaporator of low temperature Also we define input and output vectors as, Transpose of input vectors, Where, T is transpose of the matrix. (a) Two stage From my understanding, for cascade control system, the setpoint for level is fixed while the setpoint for flow is floating to ensure level meets the setpoint. d. Must always employ the derivative mode in the controller. Figure 2 gives the circuit of a two stage CE audio amplifier. Cascade refrigeration is applicable to The noise of the first stage is the most important. The complete information about an entity in a database is called a. (a) Two stage One (d) None Reduce them (d) None Third-stage voltage gain in db = 20 log 10 400 = 20 × 2.6 = 52 ∴ Total voltage gain = 40 + 46 + 52 = 138 db. The facility to easy editing, spelling check, auto pagination, lay out and printing reports b. The amplifier consists of three stages, a low gain degenerated common emitter Q 1, a high gain stage, Q 2 and the push-pull output stage, Q 3 and Q 4.Q 3 and Q 4 are commonly referred to as a push pull configuration. Cascade control can improve control system performance over single-loop control whenever either: (1) Disturbances affect a measurable intermediate or secondary process output that directly affects the primary process output that we wish to control; or (2) the gain of the secondary process, including the actuator, is nonlinear. (Ans: a), For achieving -800C temperature, cascade refrigeration used is (Ans:a), The ratio of  COP of a two stage Cascade refrigeration system vs three stage cascade system is, In a 2 stage cascade refrigeration system, cooling effect occurs in the, Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window). b. b. Used as if a 1 percent error can be tolerated Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counter flow heat exchanger where both streams enter at about 0.4 MPa. Outer Loop Tuning - put slave into Cascade and tune master controller as a normal PID loop. 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