Document Type

Restricted Campus Only

Publication Date

4-2011

Abstract

The goal of this project was to design and test a device that will measure the flow rate of condensate that is created by large, industrial scale HV AC units. This is important because depending on the volume of water generated by an HY AC unit there is the possibility to reuse the water in non-potable situations, thus conserving water supplies and saving companies money. The design must be accurate to within 5% of the actual flow rate, within the range of 0-0.5 gpm. The device must be shorter than 12 vertical inches, must be low cost and able to run off battery and AC wall power. The final requirement is the device must have a display that enables a user to read the flow rate and total volume collected, and must be able to output this data via RS-232 connection. The device consists of two separate sub-groups; mechanical and electrical. The mechanical design consists of three systems; tipping system, housing system, and drainage system. The tipping system collects water in two equally sized buckets, and tips at a known volume. The water then exits the device through the drainage system. The housing system protects the other systems and provides support for the overall design. The electrical system consists of the following: tilt switch, microcontroller, LCD, and the power supply. The tilt switch operates by sending a signal every time the device is tilted through a certain range. This signal is sent to the microcontroller, which then is programmed to calculate and output the data required for the design and sends this data both to an output in RS-232 as well as an LCD display which can be viewed by the user.

The device is subjected to a variety of tests: Calculating the total volume of water required for tip, flow rate measurement accuracy tests using a pump to simulate various flow rates, and calibration of the tipper to ensure that both sides tip at the same volume of water within an acceptable amount of variation. These tests were perfo1med on a first prototype, and based off of observations, modifications to the design were made, including re-design of the drainage system and re-sizing of the entire design. The final design specifications were sent to Cutting Edge Manufacturing to be professionally constructed.

The final prototype produced mixed results from testing. The measurement accuracy is nearly double the required tlu·eshold; an average of 10%. Problems in the individual subsystems are likely the source of this error. In the mechanical subsystem, the tipper has issues maintaining a consistent tip volume. Also the tipper bounces a significant amount when stopped by the supporting rounds. Electrically, the tip switch has some instability in counting the tips; also the microcontroller as designed cannot calculate the instantaneous flow rate. The serial output has no detectable signal, thus the device cannot output data. However, total volume and the time between tips can be displayed. Page ii

Comments

Dr. Collins, Advisor

ENGR-4382

Download

Share

COinS