Key Study of Energy Savings based on Eurovent ... · 1 Key Study of Energy Savings based on...

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Key Study of Energy Savings

based on Eurovent Classification of AHU’s Mechanical Characteristics

Thanasis Paliogiannis, Stefanos Gaitanos

AHI Carrier S.E. Europe Air-Conditioning S.A.

EinB2019 – 6th International Conference in Northern Hellas

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ABOUT AHI CARRIER SE EUROPE AIR-CONDITIONING S.A.

We provide innovative& reliable solutions for residential, commercial,

industrial & marine applications of any

scale

With strong commitment to our

environmental responsibility,

our products deliver industry-leading

energy efficiency & lead the ozone-

depleting refrigerantsphase-out

Our company is nurtured with the

values of exceptional performance, quality

& customer care, driven from our most valuable asset, our

people

Founded in Athens in 1952, our company has evolved rapidly, currently being responsible for the distribution and SEE rights of Carrier & Toshiba HVAC

products and Totaline parts & accessories, in Central and SE Europe region


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• Eurovent Certified Air Handling Unit Mechanical Characteristics

• Building Model Description

• Methods used for the Determination of System Behaviour

• Examination of Energy Savings Potential

• Summary


OVERVIEW

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SCOPE


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The test method for the mechanical performance of the casing is applicableto the comparison of different constructions – EN 1886:2009

To determine whether Eurovent Certified AHU Mechanical Characteristics canprovide a basis for the comparison of energy savings of different units


SCOPE

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EN 1886


SCOPE

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Mechanical Strength

Air Leakage

Filter Bypass Leakage

Thermal Transmittance

Thermal Bridging

• D1• D2• D3

• L1• L2• L3

• T1• T2• T3• T4• T5

G1 to F9

• TB1• TB2• TB3• TB4• TB5

M Box

M Box

M/R Box

M/R Box

M/R Box


SCOPE

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BACKGROUND


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Casing Air Leakage

Model or Real Box

• Model enclosure of at least two (2) unit sections of identical design and assembly to real AHU including at least one access door fitted with hinges and standard closures but no window

• 0.9 m ≤ Box Height & Width ≤ 1.4 m

• 10 m2 ≤ Atotal, ext ≤ 30 m2

Tested @ -400 Pa & +700 Pa

• -ve Sections: Tested @ -400 Pa

• +ve Sections (Pressure<250 Pa): Tested @ -400 Pa

• +ve Sections (Pressure>250 Pa): Tested @ +700 Pa or @ fan operating pressure whichever is greater

𝑙"## = 𝑙%400

𝑡𝑒𝑠𝑡𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒

#.01

𝑙2## = 𝑙%700

𝑡𝑒𝑠𝑡𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒

#.01

-ve +ve


BACKGROUND

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-ve +ve

𝐴𝑟𝑒𝑎 = 𝐴6789,;<9 − 𝐴>?%@;AB − 𝐴C@;787DB𝐴𝑟𝑒𝑎 = 2 𝑊𝐻 +𝐻𝐿 +𝑊𝐿 − 𝑛K 𝑙ℎ − 𝑛M(𝑊𝐻)


BACKGROUND

Casing Air Leakage

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𝐴𝑟𝑒𝑎 = 𝐴6789,;<9excluding baseframe & weatherproof roof

Steady State ΔΤ = 20 ΚModel Box


BACKGROUND

Thermal Transmittance

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MODEL


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v Office Space

• 1000 m2 of Model Space 𝐿 = 𝑊 = 10 10� 𝑚

• H = 3.20 m

• Total Window Surface of 48 m2 placed along

the S-N walls

• Uext.walls = 0.45 Wm-2 K-1

• Uwindows = 1.90 Wm-2 K-1

• Uroof = 0.40 Wm-2 K-1

• Ufloor = 0.80 Wm-2 K-1

• No Infiltration/Exfiltration

• 100 Occupants during Office Operating Hours

• Lighting Load = 16.00 Wm-2

• Miscellaneous Electrical Loads = 15.00 Wm-2

v Design ConditionsIndoor Design Conditions @ Cooling:25 oC DB/50% R.H.

Indoor Design Conditions @ Heating:22 oC DB/50% R.H.

v Typical Meteorological Year

v CitiesAthensThessalonikiHeraklionRhodes


MODEL

Building Performance Simulation Model

v Software

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HVAC System • Single Zone Constant Air Volume System with thermostatic control

• AHU equipped with a common cooling/heating coil to meet space requirements

• Cooling/Heating Coil paired with an air-cooled heat pump to provide chilled/heated water

• Unit Operating Hours: 8.00 am to 6.00 pm excluding weekends

• Fresh Air Flow Rate in accordance with minimum requirements specified in Τ.Ο.Τ.Ε.Ε. 20701-1/2017

• Heating Mode: November to April

• Cooling Mode: May to October


MODEL

Building Performance Simulation Model

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ANALYSIS


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• Additional/apparent fan power energy cost(easy to calculate)

• Leakage air cooling and heating cost requires calculation of:

1. AHU’s air supply temperature, based on AHUs Cooling/Heating Load (Cooling/Heating Coil Simulation)

2. Heat Pump’s additional energy consumption, based on AHU’s Cooling/Heating Load and Weather Conditions (Heat Pump Simulation)


ANALYSIS

Air Leakage Thermal Transmittance

• Heat Loss through AHU Casing based on mean internal and external air temperature(easy to calculate

Air Leakage & Thermal Transmittance Energy Cost for Operating Hours / Year

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Cooling

Cooling with No Space Loads

Heating

Heating with No Space Loads

Coil ON Cooling

Sensible Heat Removal ONLY

Sensible & Latent Heat Removal

IF Air Dew Point Temperature < Water Inlet Temperature *

IF Air Dew Point Temperature > Water Inlet Temperature*

𝑸𝒄𝒐𝒊𝒍̇ = �̇�𝒂𝒊𝒓𝑪𝒑,𝒂𝒊𝒓 𝑻𝒄𝒐𝒊𝒍,𝒊𝒏 − 𝑻𝒔𝒖𝒑𝒑𝒍𝒚

𝑸𝒄𝒐𝒊𝒍 =̇ �̇�𝒂𝒊𝒓 𝒉𝒄𝒐𝒊𝒍,𝒊𝒏 − 𝒉𝒔𝒖𝒑𝒑𝒍𝒚

Coil ON Heating Sensible Heat Addition

𝑸𝒄𝒐𝒊𝒍̇ = �̇�𝒂𝒊𝒓𝑪𝒑,𝒂𝒊𝒓 𝑻𝒔𝒖𝒑𝒑𝒍𝒚 − 𝑻𝒄𝒐𝒊𝒍,𝒊𝒏

Coil OFF


ANALYSIS

Common Cooling / Heating Coil Operation

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ANALYSIS


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𝑄%?< = 𝑓 𝑚𝑖𝑛 �̇�?8A𝐶@,?8A, �̇�h?9;A𝐶@,h?9;A

�̇�B;7B = �̇�?8A𝐶@,?8A 𝑇B6@@jk − 𝑇lC8j,87

�̇�h?9;A =�̇�B;7B

ΔΤh?9;A×𝐶@,h?9;A

𝑈𝐴 =1

ℎ𝐴 h?9;A+

1𝜂r ℎ𝐴 ?8A

sK

ℎ𝐴 h?9;A = 𝑥h?9;A�̇�h?9;A

�̇�h?9;A,#

#.u1

ℎ𝐴 h?9;A,#

𝑥h?9;A = 1 +0.014

1 + 0.014×𝑇h?9;A,87,#𝑇h?9;A,87 − 𝑇h?9;A,87,#

𝜂r ℎ𝐴 ?8A = 𝑥?8A�̇�?8A

�̇�?8A,#

#.u#

𝜂r ℎ𝐴 ?8A,#

𝑈𝐴lC8j,;79v?j@k =�̇�lC8j𝐿𝑀𝐻𝐷

𝑈𝐴lC8j,;<9 = 𝐶@,?8A𝑈𝐴lC8j,;79v?j@k

𝑈𝐴lC8j,9C9?j =1

1𝑈𝐴lC8j,879

+ 1𝑈𝐴lC8j,;<9


ANALYSIS


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𝑅M = 0.9978, 𝑅𝑀𝑆𝐸 = 0.0502

𝑝MK = 1.705𝐸 − 05𝑝KM = 4.365𝐸 − 06𝑝#� = 6.858𝐸 − 06

𝑒𝑓𝑓 = 𝑓 𝐴𝑚𝑏. 𝑇𝑒𝑚𝑝, 𝐶ℎ𝑖𝑙𝑙𝑒𝑟𝐿𝑜𝑎𝑑 = 𝑓(𝑥, 𝑦)

𝜂 = 𝑝## + 𝑝K#𝑥 + 𝑝#K𝑦 + 𝑝M#𝑥M + 𝑝KK𝑥𝑦 + 𝑝#M𝑦M + 𝑝�#𝑥� + 𝑝MK𝑥M𝑦 + 𝑝KM𝑥𝑦M + 𝑝#�𝑦�

𝑝## = 1.147𝑝K# = 0.09668𝑝#K = 0.136𝑝M# = −0.003331𝑝KK = −0.002015𝑝#M = −0.001576𝑝�# = 2.406𝐸 − 05


ANALYSIS

Heat Pump – Cooling Mode Efficiency Simulation

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RESULTS


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Electricity Cost = 0.145 €/kWh

Cost Difference between AHUs of Different Mechanical Performance Class in the range of 2 to 4%


RESULTS

Assumptions

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RESULTS

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RESULTS

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RESULTS

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RESULTS

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Hospital Application


RESULTS

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RESULTS

Hospital Application

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SUMMARY


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• Eurovent Certified Air Handling Unit Mechanical Characteristics can provide abasis for the comparison of AHUs Energy Savings Potential

• Pay-back period is heavily influenced by unit operating hours(application requirement) and AHU fresh air flow rate

• In terms of Air Leakage Class (L), units appear to offer competitivepay-back periods across all 4 cities, particularly in Fresh Air AHU applications

• In terms of Thermal Transmittance Class (T), units appear to offer longer pay-back periods across all 4 cities. Cities with extreme weather conditions tend tooffer the most competitive pay-back periods


SUMMARY

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QUESTIONS?


Date post:	28-Sep-2020
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