Project Subjects
Design Support for Electric Kitchens
Background and Objective
Electric kitchens have recently become widespread not only in homes but also for business use, as they
can contribute to energy savings and the reduction of environmental impact because of their low emission of radiant heat, high efﬁciency of instruments in the system, and no emission of combustion gases. However, since theamount of ventilation in electric kitchens for business use is determined based on the standards for gas kitchens,
an advantage of electric kitchens in energy savings in air conditioning (reduced amount of ventilation) has not yet
been satisfactorily attained.
In this project, we developed a support tool for designing electric kitchens that can simultaneously achieve
high energy saving and high thermal comfort, focusing on the ventilation and air conditioning in electric kitchensfor business use. Also, we developed a technique for analyzing the exhaustion of oil smoke during cooking, whichis indispensable for the measurement of ventilation efﬁciency in electric kitchens.

Main results
1. Development of prototype design support tool
A calculation function for ventilation circuits was developed to calculate the amount of ventilation inelectric kitchens considering temporal variation in the amount of ventilation between an electric kitchen and anadjoining room. This function was integrated into CADIEE, which is a tool developed by CRIEPI for designing
the indoor thermal environment of homes (Fig. 1). Also, a function to incorporate the factors such as the amountof heat generated by kitchen instruments, the speciﬁcations of air supply and exhaust fans, and the area of theventilation hood into the calculation of the amount of ventilation was added. Due to these improvements, it is now
possible to calculate the air conditioning load of each room using CADIEE while considering heat transfer due toroom-to-room ventilation [R09008].
2. Development of technique for analyzing exhaustion of oil smoke during cookinga) Development of technique for analyzing oil smoke
We developed a method for chemical measurement of organic compounds such as fatty acids in oil smoke,a principal component of the exhaust gas during cooking. This method comprises the following three procedures(Fig.2): oil smoke is sampled through a glass ﬁber ﬁlter placed on the exhaust hood (sampling); the components ofthe sample are separated via a solid-phase column using a silica adsorbent (pretreatment); and the components areidentiﬁed and quantiﬁed using a gas chromatography mass spectrometer (analysis). Our method was applied to areference sample of simulated oil smoke, and its measurement accuracy was veriﬁed to be satisfactory [V09019].
b) Application of developed analytical technique in actual kitchens
Oil smoke generated from cooking instruments for sautéing and deep-frying food in an actual kitchen(area 72m2; 300 meals/day), where gas cooking appliances are mainly used, was sampled for 18 days. Fatty acidsin the sample were analyzed by the method explained in a). The results revealed that oleic acid, linoleic acid,palmitic acid, and stearic acid are the principal components accounting for 89% of the oil smoke, and that there
was no marked change in the percentages of these components even when different types of dish were cooked(Fig.3). It was conﬁrmed that these four types of fatty acid are suitable analysis targets in calculating ventilation
efﬁciency [V09012].
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Environmental and Energy Utilization Technology
Exhaust fa n

Supply fa n

Supply fan
Exhaust fan

Duct

Modeling of
calculation targets

Air conditioning

Main improvementsof CADIEE

Heat transferfrom outdoor

Exhaust hoodCalculation ofamount of room-toroom ventilation

Heat generation
Opening
Draft

KitchenCalculation of heattransfer consideringroom-to-room
ventilation

Adjoining room (for diners)

Ventilation circuit model
Pressure of outside air(reference potential)

Air-conditioning loads fordifferent times and rooms,
Annual load of the entire
building

Fan (battery)Pressure loss(resistance)

Air flow rate(current)

Calculation pointof pressure(voltage)

Fig. 1 Calculation ﬂowchart of developed prototype design support tool
The ﬂow rate of all air is obtained by calculating the balance of the ﬂow rate and pressure of air at each node of a ventilation
circuit, similar to an electric circuit.

A glass fiber filter is placed on theexhaust hood（１）Sampling（２）Pretreatment

Amount of elution (Total amount = 1)

（２）

リノール酸
Linoleic acid
Palmitic acid
パルミチン酸1
Linearhydrocarbons
直鎖炭化水素0.8

Polycyclic aromatic
多環芳香族炭化水素hydrocarbons

脂肪酸
Fatty acids

0.60.40.2（１）0010Time

オレイン酸
Oleic acid

ステアリン酸Stearic acid（３）Analysis

Fig. 2 Flowchart of oil smoke analysis and example of analytical result(1) A glass ﬁber ﬁlter is placed on the exhaust hood. (2) Each component is separated via a solid-phase column. (3) Chromatograph of fatty acids obtained using a gas chromatography mass spectrometer indicates the clear separation of principal
components.
①7m

North②③④⑤⑥(1)

(2)
Hood1

Hood2
Targeted hood

Hood3

Hood5
Hood411%8%50%
14%①Convection oven, etc ②Rotating cooker③Fryer ④Gas range⑤Noodle cooker ⑥Soup warmer
12m

17%

Oleic acid
Linoleic acid
Palmitic acid
Stearic acid
OthersFig. 3 Layout of kitchen used and analytical result for oil smoke(1) Layout of kitchen used (Appliances 1-6 all use gas.) (2) Weight percentages of components in oil smoke (over an 18
day period)

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