How to Take Basic Readings to Show Energy Efficiency

Transcription

1 How to Take Basic Readings to Show Energy Efficiency NADCA Energy White Paper Readings & Copyright 2017 NADCA, All Rights Reserved No part of this publication may be reproduced or distributed by any means, electronic or mechanical, including photocopy, recording, or any other information storage and retrieval system, without prior written consent from the publisher. Presenters Michael White USAR, ASCS, CVI Clean Air Systems of LA, Inc. Michael C. White ASCS, CVI Clean Air Systems of LA, Inc. This presentation is not intended to be a comprehensive program covering all aspects of this topic. All technicians are encouraged to read and follow all applicable standards, codes and regulations related to this topic. It is the responsibility of each individual contractor to follow local building codes and licensing requirements and to work safely in accordance with OSHA guidelines. Disclaimer It is the contractor s responsibility to take proper precautions on each project to prevent cross contamination. Always take the health and safety of the building occupants into consideration before you conduct any cleaning procedures. All of the following tips are only general tips. They do not cover every situation and it is your responsibility to adapt these tips to the individual system you are working on. The Instructor is not responsible in any way for the work you perform after viewing this slide show. You are responsible for your own work. The views and opinions following are the instructors opinions and not necessarily the official position of the National Air Duct Cleaners Association. 1

2 Clean Components Restore Energy What We ll Learn Measuring Air Distribution System Performance Required Equipment When, Where, How of Measurements Live Demonstration Cleaned Components Restore Energy Particulate buildup over time has insulating effect on surface of coil, leading to longer cooling times & greater energy consumption How to Take Basic Buildup Readings between fins of coil increasingly restricts airflow over to Show time Energy Efficiency Clean according to ACR, the NADCA Standard NADCA White Paper on Energy Efficiency HVAC cleaning can make significant improvements in energy performance of HVAC systems. 2

3 Measuring Air Distribution System Performance Before and After Cleaning Measure cubic feet per minute (CFM) & humidity/temperature change before and after the coils. From this we can calculate the output of the system in BTUs or British Thermal Units Information obtained from readings can be put into a formula to show how cleaning has improved energy performance. Detailed information and the formula can be found at: nadca.com under Resources/White Papers Equipment Required Electronic thermometer and hygrometer: A digital instrument that measures temperature and relative humidity How to Take Rotating vane anemometer: measures air volume in CFM Basic Readings *takes basic readings to Show Energy Manometer: measures air pressure Efficiency Pitot tubes: attached to manometer & inserted into duct or air stream to measure air pressure *this method is for more advanced readings Taking Measurements NADCA White Paper provides step-by-step instructions for taking measurements: How Evaporator to Take Coil Basic Calculating Readings Temperature Readings (Delta T to Show and Delta Energy H) Efficiency Measuring CFM Return Inlet/Supply Outlet Airflow Main Supply Duct Airflow Image of duct traverse reading courtesy of 3

4 Measuring Air Distribution System Performance Before and After Cleaning IMPORTANT NOTE: Filters, dirty or clean, restrict airflow and may skew pre-and How post-cleaning to Take measurements. Basic Readings Filters must be in the same condition for both readings when to Show Energy measuring CFM before and after cleaning. Efficiency If filters are new, used, or removed for the before CFM reading, they must be the same for the after reading. Taking Measurements - Evaporator Coil Use Electronic thermometer and hygrometer: Drill holes in appropriate location in the AHU (Air Handling Unit) cabinet or ductwork connected to the cabinet Insert probe to take readings of the air entering and leaving the evaporator coil. IMPORTANT NOTE: When drilling holes near a coil, care must be taken not to drill into the coil or any other device. Ensure there is adequate clearance before drilling. Taking Measurements - Evaporator Coil Step 1. Locate spot on upstream side of coil. (Should be halfway up or across coil where typical airflow & temperature can be expected. On larger or compartmented coils, select two or more locations as needed and use average at further locations to ensure you are measuring similar temperatures.) Step 2. Drill a hole in the spot(s). Hole should be just large enough typically ¼ or 3 8 to insert probe. Step 3. Note readings for temperature and relative humidity. Step 4. Remove probe and seal hole(s) with plastic plugs, foil tape, or appropriate alternative. Repair any external insulation that may have been removed for obtaining readings. Step 5. Repeat same process on the downstream side of the coil. 4

5 Where Temperature Differential (Delta T) Readings Are Taken Measure Airflow Basic Method: Return Inlet or Supply Outlet Airflow Measure: Air velocity or air volume, (CFM) if needed, is measured at a return grill or supply register. Use How Rotating to Take Vane Anemometer Basic Four Readings CFM measurements taken at the register, in to Show each of Energy four quadrants -upper right, upper left, Efficiency lower right and lower left. Use the average of these four measurements as your CFM reading How to Take Basic Readings to Show Energy Efficiency Formula BTUs/hour = CFM x Δh x 4.5 Formula provides total heat load (sensible + latent) across evaporator coil h stands for enthalpy the total quantity of heat energy contained in a substance, also called total heat. Measurement is in BTU/lb. of dry air In order to determine h (enthalpy), both the dry-bulb temperature and relative humidity (or, as an alternative, the wet bulb temperature)of the air entering and leaving the evaporator coil is required. (PsychrometricChart or App required) 5

6 Formula Calculations Enter before & after cleaning data and the spreadsheet will calculate the increase in energy performance for you. Free download at nadca.com HVAC Cleaning Energy Audit Checklist Other Common Problems that Impact Energy Performance Duct and system leakage Closed, improperly set, or stuck dampers Filtration issues Excess flex ductwork Damaged ductwork Failed duct liner Clogged or nonfunctioning exhaust systems Deteriorating coils Poorly functioning HVAC equipment Unbalanced Air Flow Missing or broken turning vanes, dampers & other duct components and What is Total External Static External static pressure is the measurement of all of the resistance in the duct system that the fan has to work Introduction against. to For instance the filters, grills, A/C coils and the Static ductwork. Pressure It is the total of the suction pressure (negative) and the discharge pressure (positive) created by the equipment blower. 6

7 What is in a Duct System? Static pressure is one of the most important factors in Introduction HVAC to design! Simply put, static pressure refers to the resistance to airflow in a heating and cooling systems components and the ductwork. How to Setup a Gauge It takes less than five minutes to measure a system s static pressure: Step 1: Introduction Locate the to appropriate places to drill the test holes on the supply Static side Pressure (+) between the furnace and the coil, and on the return side (-) between the filter and the furnace. Center the holes for neat appearance. Stay away from any coils, cap tubes, condensate pans, or circuit boards to avoid damage. Always look before you drill. Where to Take the Readings on Air Handler Introduction to 7

8 Furnace Readings Introduction to How to Setup a Gauge Step 2: Drill test holes using a 3/8-in. drill bit. A bullet tip drill Introduction makes to a clean round hole. Make sure to use your drill, use a bit sheath to prevent from drilling into the coil. If there s duct liner inside, be sure to penetrate it to assure a good reading. Bit Sheath 8

9 How to Setup a Gauge Step 3: Push one end of the tubing onto the static pressure tip. Place the other end of the hose on the HIGH (+) pressure port of the gauge. If required, make sure the gauge is level and zero the gauge by adjusting the screw on the face with the small screwdriver. (Digital gauges each zero differently, so check owner s manual.) Example of Gauges How to Setup a Gauge Step 4: Read the supply or positive (+) static pressure by inserting Introduction the static to pressure tip in the test hole into the air stream with the tip facing into the airflow. The magnet on the tip will hold it in place while the value is read and recorded. This measurement is the pressure the fan is "seeing" on the supply side of the system. 9

10 Use the Same Tips for Gauge Tool Introduction to Picture of the Probe and How to Insert Note Direction of the Tip Introduction to AIRFLOW TIP DIRECTION 10

11 How to Setup a Gauge Step 5: Insert the static pressure tip in the test hole on the Introduction return to side with the tip facing the airflow. Static Pressure Read and record the negative static pressure. Don t forget to insert hole plugs in the test holes when you re done testing. Introduction to Introduction to 11

12 How to Setup a Gauge Step 6: Calculate the system s Total External by Introduction adding to the two values. Static Pressure Since the negative and positive signs identify the type of pressure measured, you can ignore them when adding the two values together. It makes no difference we are just adding numbers together. Example of Measurement The supply static pressure reading is (+).26 w.c. The return static pressure reading is (-).21 w.c =.47 The total system static pressure is.47 w.c. The Highs and Lows If static pressure is too high, you have evidence of problems with the system causing low airflow. Static Check Pressure for blockage in ducts, closed dampers, improper transitions, offsets or kinked flex duct. The problems can also be from the equipment and system accessories like High Efficiency cooling coil or restrictive filters. Low static pressure can also mean trouble. Low pressure may indicate leaking ductwork or plenums, missing filters, low fan speed or separated ductwork 12

13 What Does It All Mean? Doesn t it seem strange that the duct system is excluded from 98% of our industry s service agreements? Static It s Pressure clear that the pendulum has swung too far in the direction of the equipment and away from comfort. Wouldn t it be great if you were one of the 2% that actually knew how to resolve this problem? Do you think you could earn any money with this knowledge? Opportunity Static pressure allows you to "see" the system in an entirely new light airflow nearly becomes visible. Introduction Airflow is to directly connected to efficiency. Once you understand static pressureyour ability to diagnose and solve problems multiplies and see the system as a whole. The New Frontier When it comes to value, a properly installed, tested and balanced duct system is worth far more than a new Introduction furnace. to You can generate tons of duct repair and renovation work from the systems you service and clean every day. The margins are extremely high and the skills required to perform duct renovation are minimal. 13

14 Live Demonstration Thank you for Participating! 14