AHRI GUIDELINE F SI-2015 Selection Installation and Servicing of Residential Humidifiers.pdf

1、 2015 Guideline for Selection, Installation and Servicing of Residential Humidifiers AHRI Guideline F (SI) Price $10.00 (M) $20.00 (NM) Copyright 2015, by Air-Conditioning, Heating, and Refrigeration Institute Printed in U.S.A. Registered United States Patent and Trademark Office IMPORTANT SAFETY DI

2、SCLAIMER AHRI does not set safety standards and does not certify or guarantee the safety of any products, components or systems designed, tested, rated, installed or operated in accordance with this standard/guideline. It is strongly recommended that products be designed, constructed, assembled, ins

3、talled and operated in accordance with nationally recognized safety standards and code requirements appropriate for products covered by this standard/guideline. AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted industry practices. AHRI does not certif

4、y or guarantee that any tests conducted under its standards/guidelines will be non-hazardous or free from risk. Note: This guideline supersedes AHRI Guideline F-2008. For I-P ratings, see AHRI Guideline F (I-P) 2015. TABLE OF CONTENTS SECTION PAGE Section 1. Purpose 1 Section 2. Scope .1 Section 3.

5、Definitions.1 Section 4. Factors Affecting Humidification Load 2 Section 5. Humidification Load Determination .3 Section 6. Residential Humidifier Selection 6 Section 7. Installation Best Practices .8 Section 8. Servicing Best Practices 10 TABLES Table 1. Humidification Load Required, L/day .4 Table

6、 2. Correction Factor for Other Indoor Temperatures and RH Conditions 4 Table 3. Selection Based on Water Types and Hardness 6 APPENDICES Appendix A. References Normative 11 Appendix B. References Informative 11 Appendix C. Periodic Maintenance Checklist Informative .12 AHRI GUIDELINE F-2015 (SI) 1

7、SELECTION, INSTALLATION AND SERVICING OF RESIDENTIAL HUMIDIFIERS Section 1. Purpose 1.1 Purpose. The purpose of this guideline is to establish, for residential Humidifiers: definitions; factors affecting Humidification Loads; determination of Humidification Load; equipment selection; installation pr

8、actices; and servicing practices. 1.1.1 Intent. This guideline is intended for the guidance of the industry, including manufacturers, engineers, installers, contractors and users. 1.1.2 Review and Amendment. This guideline is subject to review and amendment as technology advances. Section 2. Scope 2

9、.1 Scope. This guideline applies to Central System and Self-contained Humidifiers, as defined in AHRI Standards 611 (SI) and 621 (SI), installed in residential and small commercial applications. Section 3. Definitions All terms in this document will follow the standard industry definitions in the AS

10、HRAE Terminology Site (https:/www.ashrae.org/resources-publications/free-resources/ashrae-terminology) unless otherwise defined in this section. 3.1 Humidifier. A device used to add moisture to the air. 3.1.1 Central System Humidifier. A type of Humidifier that adds moisture to the air stream of a c

11、entral air system. It may be mounted in or on the following: 3.1.1.1 Return air duct 3.1.1.2 Return air plenum 3.1.1.3 Supply air duct 3.1.1.4 Supply air plenum 3.1.1.5 By-pass (supply to return) 3.1.1.6 Heating or cooling central air system 3.1.2 Self-contained Humidifier. A type of Humidifier inte

12、nded for installation independent of a central air system. Self-contained humidifiers may or may not be installed directly within the humidified space. Note this may also be referred to as Self-contained Humidifier for Residential Application. 3.2 Humidification Capacity. The maximum amount of humid

13、ity that a humidifier can add to the air, expressed in L/hr or kg/hr. 3.3 Humidification Load. The amount of water that needs to be added to the air by the humidifier in order to satisfy the conditions desired in the space expressed in Liter/day, or kg/hr. 3.4 Humidifier Types. Different kinds of Se

14、lf-contained Humidifiers for Residential Application. 3.4.1 Atomizing Humidifier. Humidifiers which disperse or spray a fine mist of liquid water directly into the air. Some examples of Atomizing Humidifiers are centrifugal, nozzle, and ultrasonic. 3.4.2 Heated Tank Humidifier. Humidifiers which use

15、 electricity, gas, or another energy source to boil water into steam. The steam is then dispersed directly into the conditioned space or into a ducted airstream. Some examples of Heat Tank Humidifiers include electric and electrode. AHRI GUIDELINE F-2015 (SI) 2 3.4.3 Wetted Media Humidifier. A type

16、of Humidifier intended for duct applications in which water passes over media placed in the air stream. As the air passes through the wetted media, water evaporates increasing the moisture content of the air stream. The water not evaporated is drained, retained in the reservoir, or returned to a tan

17、k for recirculation. Some examples of Wetted Media Humidifiers are wetted pad and rotating drum. 3.5 Rating Conditions. A fixed set of environmental conditions which lead to a given level of performance. Varying these conditions will result in varying humidifier performance 3.5.1 Standard Rating Con

18、ditions. A set of Rating Conditions that are standardized and used as the basis of comparison for performance characteristics. 3.6 Should. “Should” is used to indicate provisions which are not mandatory but which are desirable as good practice. 3.7 Water Characteristics. 3.7.1 Water Types. 3.7.1.1 P

19、otable Water. Domestic water from a municipal or well source that meets standards for consumption. May also be referred to as tap water or municipal water. 3.7.1.2 Softened Water. Water that has been conditioned by the ion exchange process (commonly referred to as a water softener) to exchange calci

20、um and magnesium ions with sodium or potassium ions. 3.7.1.3 Demineralized Water. Water which is largely free from particles and dissolved substances having a conductivity below 0.2 micro-Siemens per centimeter (S/cm). This includes deionized (DI) and reverse osmosis (RO) water, and distilled water.

21、 3.7.1.4 Untreated Water. Water from a rainfall, river, or lake source that has not been treated. Untreated water is not suitable for use in most humidifiers. 3.7.2 Water Hardness. The amount of dissolved minerals (e.g., calcium, iron, magnesium, and sodium) that are naturally present in the water a

22、nd are expressed in grams/Liter or ppm. Hardness in water contributes to the formation of mineral scaling inside of humidifiers and may affect the performance of the humidifier. 3.7.2.1 Naturally Soft Water. Water with a dissolved solid content usually below 0.06 grams/Liter or 60 ppm. 3.7.2.2 Moder

23、ate Hard Water. Water with a dissolved solid content of 0.060 to less than 0.120 grams/Liter or 60 to less than 120 ppm. 3.7.2.3 Hard Water. Water with a dissolved solid content of 0.120 to 0.180 grams/Liter 120 to 180 ppm. 3.7.2.4 Very Hard Water. Water with a solid content of more than 0.180 grams

24、/Liter or 180 ppm. Section 4. Factors Affecting Humidification Load 4.1 General. The following should be used as a basis for estimating the Humidification Load required: 4.1.1 Outdoor design conditions 4.1.2 Indoor design conditions 4.1.3 Size and physical characteristics of residence 4.1.3.1 Condit

25、ioned space volume 4.1.3.2 Tightness of structure, insulation, storm windows and doors or equivalent, etc. AHRI GUIDELINE F-2015 (SI) 3 Note: Some older structures may have inadequate protection against water vapor transmission through walls, which may result in damage from excessive moisture. 4.1.4

26、 Quantity of Outdoor Air Entering the Conditioned Space. 4.1.4.1 Mechanical and Natural Ventilation. 4.1.4.1.1 Mechanical ventilation may include fans, blowers, energy recovery ventilators (ERVs), and heat recovery ventilators (HRVs) 4.1.4.1.2 Natural ventilation may include operable windows and doo

27、rs 4.1.4.2 Open fireplace dampers greatly increase the amount of outdoor air added to the heated volume of the structure. Satisfactory performance of a Humidifier, as applied to a given structure, is often based upon these dampers being closed. 4.1.5 Internal Load Generated. 4.1.5.1 In calculating h

28、umidity load requirements in residential applications, internal load factors are normally not included because of the variation in living habits, e.g., bathing and laundry habits, cooking, number of occupants, etc. However, these may be included at your discretion. 4.2 Outdoor Design Conditions. The

29、 outdoor design conditions to be used for calculating humidity requirements are -6.7C and 70% RH, or local design conditions may be used. 4.3 Indoor Design Conditions. The indoor design conditions to be used for the calculation of humidity requirements are 21.1C and 35% RH. 4.4 Ventilation and infil

30、tration. Ventilation in a residence is in most current practices handled by natural or mechanical ventilation. Air leakage or infiltration is air flow from open doors or windows, as well as unintentional openings in the home, such as cracks in walls, or door leakage. For ventilation, some installati

31、ons use a positive inlet duct or a mechanical air recovery exchanger. Since there is a large stock of housing that has been constructed over decades and governed by different or minimal code requirements, the load estimates should add both the infiltration and ventilation rates. 4.4.1 Infiltration.

32、Infiltration is variable. For humidifier sizing, the infiltration may be estimated as follows: 4.4.1.1 For tight construction, use air change per hour. 4.4.1.2 For average construction, use 1 air change per hour. 4.4.1.3 For loose construction and/or maximum ventilation factor, use 1.5 air changes p

33、er hour. The ASHRAE Handbook HVAC Systems and Equipment defines a tight house as one “.assumed to be well insulated and to have vapor retarders, tight storm doors, windows with weather-stripping, and a dampered fireplace. An average house is insulated and has vapor retarders, loose storm doors and w

34、indows, and a dampered fireplace. A loose house is generally one constructed before 1930 with little or no insulation, no storm doors, no insulated windows, no weather-stripping, no vapor retarders, and often a fireplace without an effective damper.” Any air exhausted from or fresh outdoor air being

35、 introduced into the home will increase the Humidification Load. Section 5. Humidification Load Determination 5.1 There are 2 methods of load calculations presented in this section. The first method, described in Section 5.2 is the simplest and uses several assumptions to generate a humidification l

36、oad for the home. A more detailed method is presented in Section 5.3, and it allows the user to specify conditions for weather and indoor design humidity levels beyond that of the simplified method. Regardless of what method is chosen, homes that include fresh air ventilators, specialized exhaust sy

37、stems, or loose fitting AHRI GUIDELINE F-2015 (SI) 4 fireplace dampers should also follow the calculation in Section 5.4 to account for these devices. 5.2 A simple method for estimating the humidification load is presented below. 5.2.1 Step 1. Begin by determining the volume of the home in cubic met

38、ers. A simple way to achieve this involves multiplying the floor area by the average ceiling height. Be sure to include the basement in the calculations. For more accurate calculations, consider calculating the volume for each individual room and summing the results. 5.2.2 Step 2. Match the result t

39、o Table 1 below. Refer to Section 4.1.3.2 for home construction tightness. Note that Table 1 assumes an indoor condition of 21.1C and 35% RH. 5.2.3 Step 3. If your indoor condition varies from the result, multiply it by one of the correction factors in Table 2 that reflects your actual design condit

40、ion. Ideal humidity levels for human health are between 40 and 60% RH, however it is good practice to limit the relative humidity to around 35% during very cold months. This is to protect the home structure from moisture migration, particularly in average and loosely constructed homes. Please note t

41、hat some modern controls feature automatic setbacks to reduce the risk of condensation. 5.2.4 Step 4. A single occupant can generate up to 1.9 Liters per day (L/day) of humidity through activities such as cooking, cleaning, showering, and laundry. You can choose to reduce the load by 1.9 L/day per o

42、ccupant. Due to the variability of these activities it is common practice to leave the load uncorrected from step 3, as this also provides a safety factor for equipment sizing. Table 1. Humidification Load Required, L/day1,2Type of Construction Volume of Building, m3 227 282 340 453 566 680 906 1133

43、 Tight 12.7 15.7 19.0 25.3 31.6 38.0 50.6 63.3 Average 25.3 31.5 38.0 50.6 63.2 75.9 101.2 126.5 Loose 38.0 47.2 56.9 75.9 94.8 113.9 151.7 189.8 Notes: 1. Loads shown in the table are based on indoor conditions of 21.1C and 35% RH with -6.7C and 70% RH outdoors. 2. An amount of 7.6 liters per day m

44、ay be deducted from these figures if it is desired to take credit for internal sources of moisture (based on a family of four). Table 2. Correction Factor for Other Indoor Temperatures and RH Conditions Temperature Indoors 21.1C 23.9C Indoor % RH 30% 35% 40% 30% 35% 40% Correction Factor 0.8 1.0 1.3

45、 1.0 1.2 1.4 Note: This table provides the correction factor to use for other indoor temperatures and RH conditions. Multiply Humidification Load Required from Table 1 by the appropriate correction factor in Table 2. 5.3 A more exact humidification load can be calculated using the formulas presented

46、 below: 5.3.1 Step 1. Begin by determining the volume of the home in cubic feet. A simple way to achieve this involves multiplying the floor area by the average ceiling height. Be sure to include the basement in the calculations. For more accurate calculations, consider calculating the volume for ea

47、ch individual room and summing the results using Equation 1. AHRI GUIDELINE F-2015 (SI) 5 V = hlw 1 Where: h = Height, m l = Length, m V = Volume, m3w = Width, m 5.3.2 Step 2. Apply Equation 2 or Equation 3 to determine the humidification load. =() + 2 or = ()33,082 + 3 Where: a = Conversion factor,

48、 1,000 grams/kg D = 24 hours/day H = Humidification Load requirement in L/day L = Other moisture losses in L/ day R = Calculated air changes per hour S = Contribution of internal moisture sources in L/day V = Total indoor conditioned volume of space being humidified, m3Wi = Moisture content of air a

49、t indoor design conditions in grams/kg Wo = Moisture content of air at outdoor design conditions in grams/kg = Density of water, 1.00 kg/L of water = Specific volume of moist air at indoor design conditions, 0.848 m3/kg of dry air 5.3.3 Example. 5.3.3.1 Space being humidified (volume of the building): V = 12.2 m wide 15.2 m long 2.4 m high = 453.1 m35.3.3.2 Air changes per hour (tight construction) = 1/2 (See Section 4.1.3.1) 5.3.3.3 Assume S=L=0 5.3.3.4 Wi(indoor) at 21.1C howeve