17_Microclimatic_factors/Work procedure 1/7 Measurement of selected microclimatic factors Study group: Year of study: Objective: Determine microclimatic conditions in the classroom. Find out whether they match the thermal comfort conditions and the prescribed values for a laboratory. Tasks: 1. Measure the temperature in the room.. Measure the atmospheric pressure.. Measure the relative air humidity with a hair hygrometer. 4. Determine the relative air humidity by psychrometric method using a table and a nomogram. 5. Compare the results obtained in item 4 with the relative air humidity measured by the hair hygrometer. 6. Read the maximal air humidity for the corresponding room temperature from the table and calculate the absolute air humidity. Use linear interpolation to establish the values that are not exactly listed in the 7. Measure the dimensions of the room and calculate its volume V in m³. 8. Calculate water vapour mass m in the room using the calculated room volume V. 9. Compare measured results to standard values valid for laboratories (schools) found in the literature. Enter relevant source of data. 1. * Determine and discuss the corresponding human thermal comfort conditions using the psychrometric chart. 11. Discuss and explain possible differences. Recommended tools and devices: aneroid barometer, room thermometer (liquid or bimetallic), hair hygrometer, Assman psychrometer, August psychrometer, psychrometric chart, psychrometric nomogram, psychrometric tables, tables of saturated vapour density Procedure: 1. Work alone.. Measure the atmospheric pressure p with aneroid barometer.. Measure the room temperature t with at least 5 room thermometers located in different places. Take measurement uncertainty into account. 4. Measure the relative air humidity rel with the hair hygrometer. 5. Determine the relative air humidity rel using Assman psychrometer: a) Insert a strip of gauze into the metal casing of the wet thermometer bulb. b) Drip some distilled water on the gauze so that it shall not overflow into the device. c) Turn the flywheel of the psychrometer clockwise. d) Wait 5 6 minutes until the temperature stabilizes in the "wet" thermometer. Keep the gauze sufficiently wet in the "wet" thermometer. Keep the fan running. e) Read the temperature from the so called dry thermometer t d and wet thermometer t w. f) Determine the relative air humidity using of the psychrometric tables and the nomogram. If needed, use interpolation. 6. Determine the relative air humidity rel using August psychrometer: a) Check, whether the gauze on the mercury reservoir of the wet thermometer is damp. b) Read the temperature of so called dry thermometer t d and wet thermometer t w. c) Determine relative air humidity using of the psychrometric chart and the nomogram. If needed, use interpolation. 19.9.17
17_Microclimatic_factors/Work procedure /7 Study group: Year of study: 7. Fill in all entries in the part "Measurement results". 8. Calculate absolute air humidity abs and corresponding water vapour mass m for each determined value of relative air humidity. 9. Explain possible differences in temperature at different places. 1. Based on the measured values, determine and discuss the corresponding human thermal comfort conditions using the psychrometric chart. 11. Discuss and explain the obtained results. Applied equations: % 1 [kg/m ] Note Orange painted cells have to be filled in BEFORE your arrival on practical training. Green painted cells have to be filled during the measurement, or later during protocol processing. Parts of the procedure denoted in italics designate your homework processing measurement results at home. 19.9.17
17_Microclimatic_factors/Measurement sheet /7 Measurement of selected microclimatic factors Date of the measurement: I have studied the theory for practical training from: Study group: Year of study: Time of the measurement: (specify a complete bibliographical reference including appropriate chapter and page designation) Used devices and tools (orange color = assumend, green color = really used): Object of measurement: Measurement results: Tab. 1: Recorded atmospheric pressure, air temperature and relative humidity. Atmospheric Location of the barometer pressure Measurement Relative air Location of the hair hygrometer humudity Measurement Location of the room thermometer / Description Air temperature of the thermometer (measurement uncertainty) p [mmhg] ϕ rel [%] t [ C] p [kpa] 1... 4. 5. Room dimensions: Width (from the window to the opposite wall): w = cm = m Length (from the projection board to the opposite wall): l = cm = m Height (from the floor to the ceiling): h = cm = m Room volume: V = m 19.9.17
17_Microclimatic_factors/Measurement sheet 4/7 Study group: Year of study: Tab. : Determination of the relative air humidity by the psychrometric method. Parameter Assman psychrometer Time elapsed from the beginning of practical training [min] August psychrometer Location of the psychrometer Temperature showed by the dry thermometer t d [ C] Temperature showed by the wet thermometer t w [ C] Temperature difference Δt= t d t w [ C] table [%] ϕ rel nomogram [%] ϕ rel Maximal air humidity (according to the table) [g m ] Date and teacher's signature: 19.9.17
17_Microclimatic_factors/Result processing 5/7 Measurement of selected microclimatic factors Date of the measurement: Used devices and tools: Study group: Year of study: Time of the measurement: 1 1 Object of measurement: 1 Results: Tab. 1: Recorded atmospheric pressure, air temperature and relative humidity. Atmospheric p p Location of the barometer pressure [mmhg] [kpa] Measurement 1 Relative air ϕ Location of the hair hygrometer rel humidity [%] Measurement 1 Location of the room thermometer / Description t Air temperature of the thermometer (measurement uncertainty) [ C] 1... 4. 5. Tab. : Determination of the relative air humidity by the psychrometric method. 6 Parameter Time elapsed from the beginning of the practical training [min] Location of the psychrometer Temperature showed by the dry thermometer t d [ C] Temperature showed by the wet thermometer t w [ C] Temperature difference Δt= t d t w [ C] table [%] ϕ rel nomogram [%] ϕ rel Maximal air humidity (according to chart) [g m ] Assman psychrometer August psychrometer 19.9.17
17_Microclimatic_factors/Result processing 6/7 Study group: Year of study: Room volume: V = m 1 Tab. : Calculated absolute air humidity and water vapour mass. Enter correct units. Absolute air humidity Water vapour mass Hair hygrometer Assman psychrometer August psychrometer Table Nomogram Table Nomogram Discussion: Physical principle of used methods of temperature, air humidity and atmospheric pressure measurements. Evaluation of measurement conditions and the effect of the external environment. (E.g. location of the room, weather.) Explain possible temperature differences measured at different places in the room and compare them with the "dry" thermometer of the psychrometer. Explain the impact of the time elapsed from the beginning of the practical training on the recorded values of temperature and humidity. How does the number of people in the room impact the measurement results? Comparison of determined values of temperature, humidity and atmospheric pressure with "standard" (required) values for laboratory. Enter complete and correctly cited references of sources, from which you took the standard (required) values. Compare and discuss the results obtained from both psychrometers. 19.9.17
17_Microclimatic_factors/Result processing 7/7 Study group: Year of study: Determine and discuss the corresponding human thermal comfort conditions using the psychrometric chart. Conclusions: Summary of main results and their biophysical interpretation. The importance of determinig the microclimatic factors in medicine and medical research. References: (For example, from where you studied the theroretical background, from where you got the tables used in calculations, from where you got the psychrometric chart... Cite references in correct form.) Overall max. 9 Bonus max. 6 Score: Date and teacher's signature: 19.9.17