As residents of nursing homes for the elderly are mostly occupied with people who have difficulty in evacuating themselves, what facility staff need to do at the time of fire is many and varied. Fire drill is extremely important for facility staff to respond appropriately in case of fire.
Past questionnaire surveys indicate that facility staff do not know whether their fire drill is good or bad, and that many staff are uneasy about responding to fires at night. However, no method has been established to evaluate the quality of fire drill. So, in this research, we construct the method to evaluate the contents of the fire drill such as the staff behavior. The purpose is to make it possible for staff to know the improvement point of the fire protection system of their own facility including human response, and to reduce anxiety of the staff by that.
In order to evaluate the behavior of the staff in the fire drill, first, set the tactics that should be performed when the target facility fires at night. This tactic incorporates horizontal evacuation assuming night fire of nursing homes for the elderly. Next, the extent to which the fire drill actually conducted at the facility has been achieved for the tactics is evaluated for each of the following indicators.
(1) Evacuation characteristics of the facility: Evaluate by the ratio of Proposal estimated evacuation time (it means the time required to temporarily protect all residents in the fire compartment from smoke etc. and to prevent the outflow of smoke etc. to other fire compartments. it is calculated using the necessary flow distance and the required time and movement speed of the action obtained from the previous report) to evacuation target time
(2) The appropriateness of role assignment is determined by the ratio of the time required for each staff member to the expected evacuation time (the time calculated from the action taken and the evacuation route taken in the fire drill and the required time etc. used for the Proposal estimated evacuation time).
(3) Appropriateness of staff flow line: Evaluate by the ratio of movement distance of conventional estimated evacuation time to movement distance of proposal estimated evacuation time.
(4) Efficiency of action: Evaluate the ratio of the evacuation completion time of the actual fire drill to the conventional estimated evacuation time.
(5) Basic action: Evaluate by the implementation rate in the actual fire drill for the action group necessary for the horizontal evacuation tactic set in advance.
(6) Compartment formation: Evaluate how many places where the division of the fire source and surrounding space and the smoke exhaust operation are required have been carried out.
A case study of fire drill evaluation was conducted by applying the above evaluation method to the fire drill that was actually conducted at the nursing homes for the elderly. The fire drill was conducted at three facilities, and at two of them, the fire drill that has been conventionally performed at the facility and that suggested the flow line and the flow of implementation from the authors were performed. It was confirmed that the results of the case study were able to extract the features of each fire drill, such as the lack of actions related to heat and smoke confinement in the conventional fire drill.
Recently, the methods and techniques for adjusting the local space composition of workplaces and personal physical environments have been gradually optimized. Composite services of various technologies, such as those from the internet of things and information and communications technology, have also improved. The development of corresponding technology has made more alternative work styles accessible to office workers; that is, workers can now adjust their working environment according to their own preferences, all with the aim to create workplaces that optimize the capabilities of all. Such optimization is also one of the more effective proposals to further improve intellectual productivity. Therefore, finding the best office design for workers is currently considered a topic of utmost importance.
This study aimed to identify workers’ ideal preferences for office environment and space design, as well as the characteristics of each type of ideal office design. An online questionnaire survey targeted at Japanese workers was used to collect data on the attributes of current office workers, such as intellectual productivity, office space preferences, personality, gender, and occupational types.
To investigate worker’s preferences for different office environments, we performed the following.
(1) We selected 20 photos that featured elements that affect spatial design and impact intellectual productivity. Then, questions were asked about office design preference and impression evaluation words for each photo, and answers were collected and analyzed (Table2).
(2) Office photographs were categorized into three groups according to workers’ corresponding analyses about office design preference and impression evaluation words.
(3) Workers were categorized, and the characteristics of each category were examined; these were then compared with average office design preferences.
(4) To clarify the overall tendency of workers’ preferences for office design, impression evaluation word scores were combined with the factor load of the preference degree of worker types.
The results were as follows:
(1) According to the impression evaluation words, office photos were divided into three groups: G1=Open and Spacious, G2=Typical and Conservative, and G3=Playful (Fig. 1, Table3).
(2) Regarding office design preferences, workers were divided into four types. The characteristics of these four types were as follows: T4_1 liked G2 but did not like G1 and G3, T4_3 liked G2 the most and G3 the least, T4_2 and T4_4 both liked G1 and demonstrated slight differences in their evaluations of G2 (Fig. 4, Fig. 5).
(3) There was a high correlation between the impression evaluation words scores of the three photo groups and the factor load of worker types (Table5).
(4) Workers had different preference characteristics based on their type. However, the general tendency of each type, when plotted as vectors, showed that: T4_1 tended to strongly prefer G2, T4_3 tended to balance between G1 and G2, while T4_2 and T4_4 tended to prefer both G1 and G3, and, among these, they preferred G1 over G3 (Fig. 6).
With these clarifications on preferred characteristics for office design among different types of professionals, we expect to help in providing a suitable office design for each type of worker.
In houses having a crawl space with insulated foundation walls and a non-insulated floor over the crawl space, if the entire crawl space can be heated, then the entire floor will be heated. As a result, the entire first floor space will become the radiant heating environment. We call this heating system as the “crawl-space heating system”. This system has low risks of vascular disorders such as cerebrovascular disease caused by the large temperature differences between the rooms on the first floor.
In this paper, we propose a method to estimate the maximum heat loss from the crawl space to the foundation walls and the ground for 24-h continuous crawl-space heating, which is used to estimate the required heating capacity of the heat source equipment.
Our proposed estimation method is outlined as follows. This method uses the feature in that the heat conduction equation and boundary conditions used for heat loss calculation are linear when the thermal properties (density, specific heat, and thermal conductivity) of the object can be regarded as constant. We express the temperature fluctuations of the crawl space and those outdoor by superposing the unit temperature fluctuation. Heat losses under the conditions of each unit temperature fluctuation are calculated by numerical simulations, and they are expressed by formulae that use the insulation performances of the foundation and the thermal conductivity of the ground as explanatory variables. By superposing them in accordance with the original temperature fluctuations, estimating the heat loss at any insulation performance of the foundation, thermal conductivity of the ground, temperature of the crawl space, and outdoor temperature is possible. This method is useful when designing crawl-space heating because maximum heat loss can be estimated simply by substituting values in accordance with conditions into the proposed equations without using a numerical calculation.
First, we outline this estimation method. Subsequently, the influences of outdoor air temperature used for numerical simulation, crawl space model and the ground to be calculated, heating period, and the thermal properties of the ground (density, specific heat, and thermal conductivity) on the calculation result are examined, and the calculation conditions for numerically calculating heat losses under the conditions of each unit temperature fluctuation are determined. Furthermore, as it is necessary to use the values of the same time when superposing the heat losses calculated under the conditions of each unit temperature fluctuation, the suitable time for estimating the maximum heat loss is examined. Thus, we derived formulae that estimate heat losses under the conditions of each unit temperature fluctuation according to the insulation performance of the foundation and the thermal conductivity of the ground using multiple regression analysis, and we proposed equations to estimate the maximum heat loss depending on the area of the crawl space, perimeter length of the crawl space, and area of the foundation walls.
As natural ventilation significantly contributes to energy savings and enhances comfort, it has been adopted in many buildings. However, to maintain a comfortable room environment, including the lower limit control for room temperature, it is necessary to control the natural ventilation rate by adjusting the opening area or opening time (referred to as opening ratio). Thus, we proposed a new airflow balance simulation tool, based on Proportional-Integral-Derivative (referred to as PID) control theory, to evaluate the performance of natural ventilation control in office buildings. The proposed tool can approximately solve the thermal and airflow balance by simply adding to the existing thermal load calculations. We focused on buoyancy driven ventilation, and analyzed the following parameters using the proposed simulation tool: change in neutral pressure level, thermal load reduction, and room environment.
First, when natural ventilation rate is adjusted by PID control, controllability varies depending on the values of proportional gain, integral gain, derivative gain (Kp, Ki, and Kd) and calculation time interval. Therefore, parametric analysis was considered the most appropriate technique for evaluation.
Next, following the study of the calculation method in Chapter 4, the authors confirmed the fundamental effect of natural ventilation control using the proposed simulation tool. A ten-story buildings was used to analyses the performance of the proposed method. 1) The authors calculated characteristics values for specific representative week and months in the year. Under Tokyo weather conditions, opening ratio was operated from April to May and from October to November. There was no significant difference in the amount of heat extraction between “Controlled” and “Uncontrolled”natural ventilation. On the other hand, when lower limit for room temperature control was introduced, the number of hours at temperatures of 24 °C or less had decreased by 18.2 h. 2) The authors also calculated air changes per hour and natural ventilation hours due to the introduction lower limit for room temperature control. When lower limit for room temperature was introduced, the opening ratio of the lower floor had decreased. Subsequently, because of neutral pressure level raised, the number of natural ventilation hours on the nine-story or higher had increased. 3) The authors calculated room air temperature, natural ventilation hours and equipment load due to the alternative lower limit for outdoor temperature when natural ventilation was introduced. When the lower limit for outdoor temperature was 15 °C, the heat extraction increased by approximately 1.8 times and the equipment load was reduced by 2.1 % compared to the lower limit outdoor air temperature, which was 18 °C.
In this paper, the chimney air temperature is calculated as the average value of the interior zones of each floor. In the next paper, the authors will propose a new calculation method to solve the chimney air temperature and improve the accuracy of the performance evaluation of office buildings with natural ventilation control.
Simple thermosyphon solar water heaters (SWHs) which are integrated with solar collectors and storage tanks were widely used in 1970-1980s in Japan. According to the afterward economic development, however, they are rapidly shrinking even though its environmental benefit. In order to rejuvenate the solar thermal systems, this study aims to evaluate its correct performance to show potential users and to propose new ideas to increase its efficiency by manufacturers.
In part1, a long-term field test of three SWHs was conducted in Tsukuba, Japan. Each SWH was connected to one of three secondary distribution systems and switched to the other systems in rotation over the tests. In the secondary distribution systems, there are S1-system in which solar hot water is sent to a bathtub and a shower only, S2-system in which users can select hot water from SWH or an auxiliary gas boiler by switching a valve depending on the solar water temperature, and S3-system in which the auxiliary gas boiler works automatically by the device named the connection unit. The demand hot water temperature is 40 degC and the flow rate is periodically changed to one of the standard flow patterns matching to their distribution systems.
The collected data from 1st Apr., 2017 to 28th Feb., 2019 was sorted to the three seasons, summer, spring and autumn, and winter, after eliminating rainy days. Next, the average performance in each combination of the season and the secondary system were analyzed. Then the average value of three seasons was deemed as the annual average performance. As the results, S1 showed the highest annual SCOP as 2.10-3.50 though S2 and S3 showed 1.25-1.62. There are two reasons of the good performance in S1. First, the heat loss in the secondary pipes is highly eliminated in S1 because of the less frequent of hot water supply, which is relating to the fact that the Japanese traditional SWHs has no insulation on their secondary pipes. Second, there is no additional electric consumption from controllers and a pressure device. From the viewpoint of the net solar energy efficiency, S1 show the 30.1-37.1% which compares significantly well with PV systems.
From the multiple temperature data in the tanks, important knowledge was gained as follows. First, the tank is estimated as fully mixed in the collecting period in all SWHs. Second, SWH1 showed the large heat loss in the storage period, which made the tank performance low. Third, all SWHs kept good temperature stratification while hot water is supplying. Finally, the higher part temperature in SWH3 rose again soon after finishing supply which is expected that the highest layer still remains solar heat regardless of the last supply.
In conclusion, S1 shows the excellent performance but S2 and S3 need to save electrical consumption and to reduce the heat loss. Some SWHs need to add the insulation of the tanks or optimize internal tank flow. Part2 is going to report the detailed computer analysis which simulate these SWHs and the secondary distribution systems correctly.
To obtain basic data for prevention of heat stroke during construction work in a hot environment, we analyzed the effects of wearing ventilated work wear (VWW) and water intake (RWI). First, experiments were carried out with nine male form workers in an artificial climate chamber (AC) at 34°C. Second, measurements were carried out with four male form workers and one male rebar placer at an outside construction site (CS) for four days in August 2017. It was carried out from 8:00 to 17:00 and was divided into four shifts split up by breaks as follows: 8:00 to 10:00, 10:30 to 12:00, 13:00 to 15:00; and 15:30 to 17:00. Activity amount (ACT) was continuously measured. WBGT was measured in the CS. The sweat rate (SR), the rate of naked body weight loss (RBWL, only in the AC), body weight loss while fully clothed (RBWLC), and RWI were each measured and calculated as the difference between the values before and after work per unit time. Evaporation rate (ER) was defined as the sum of RBWLC and RWI. SR in the CS was estimated from the ER by using the regression equation between ER and SR in the AC data.
In the AC experiment, the SR during work was constant and RBWL was negatively correlated with RWI, those were statistically significant, regardless of whether the workers wore VWW. The RWI and SR of workers not wearing VWW were significantly higher than those of workers wearing VWW. RWI increased significantly and RBWL decreased as ACT increased. This is the reason that RBWL was negatively correlated with the RWI in the AC.
In the CS experiments, the SR of workers not wearing VWW increased significantly as WBGT increased, but the RWI did not change significantly; as a result, RBWL increased significantly with WBGT. The SR of individuals wearing VWW, which was lower than that of those not wearing VWW, remained almost constant with increasing WBGT, whereas RWI did not increase with WBGT. As expected from these results, RBWL remained constant as WBGT increased and was consistently lower than that of workers not wearing VWW. The ER of works in the CS was significantly higher than that of those in the AC due to the difference between the averaged ACT in the AC (1.8 Mets) and CS (2.4 Mets). In the CS experiments, we estimated the dewatering ratio (DR) by body weight loss while fully clothed (BWLC), since BWL was not measured. The fluctuation during working shifts of BWLC and DR of workers was compared between those wearing and those not wearing VWW on hot two days. In the shifts, the BWLC of workers not wearing VWW was significantly higher than that of those wearing VWW. Furthermore, in the breaks between shifts, the amount of water recovered by workers not wearing VWW was significantly lower than that of those wearing VWW. As a result, after the last shift, the average DR (2.03) of workers not wearing VWW was higher than that of those wearing VWW (1.53).
We supposed there is a limit to the amount of water that workers in a construction site can drink. Thus, we verified that, in the CS setting, RBWL increased with increasing WBGT mainly due to insufficient RWI, but could be partly decreased by using VWW, which decreased the SR.
The energy input for building operations is mainly composed of fossil fuel-based energy carriers, and therefore accounts for a large proportion of global greenhouse gas emissions. Thus, significant effort such as application of heat pumps has been focused on boosting renewable energies in building to decrease the energy demand and its related emissions. However, the conventional heat pump systems proposed such as air source heat pump or ground source heat pump systems commonly employ only one renewable energy sources to meet the cooling and heating demands. Each renewable energy source has its own advantages and disadvantages: solar radiation is a type of flow energy and is quantitatively limitless, but its availability is intermittent; geothermal energy is a stable stocked energy source but is quantitatively finite. Therefore, the combination of various energy sources has been proposed and practiced to account for their shortcomings.
In this study, we developed a multiple source and multiple use heat pump (MMHP) system which use renewable thermal energy sources around building. In the MMHP system, multiple heat sources such as solar heat, geothermal heat and air source are utilized and multiple thermal uses such as cooling, heating and domestic how water supply are used in light of heat source temperature. We developed a unique sky heat source heat pump that can use solar heat and air heat. A double-helix underground heat exchanger that can be used in conjunction with a heat pump is proposed to achieve a daily cycle operation of MMHP system. In addition, we developed water source heat pumps for domestic how water supply, floor heating and air conditioning based on commercial products. The MMHP system is expected to achieve a higher efficiency than conventional heat pump systems. Since the MMHP system is a network with distributed machines, it is easy to cope with the different scale and application and can extended according to the size and application of various buildings. To evaluate the performance and applicability of MMHP system, an experimental house called RE house was constructed in Chiba, Japan. Several self-developed water heat pumps and ground heat exchanger were used to build the MMHP system.
We conducted summer and winter field experiments to investigate the performance of each heat pump and the whole system. From the results, we can draw the following conclusions: 1) adoption of PVC pipe and decentralized pumping system helped heat transfer power and water piping cost. 2) the sky source heat pump achieved a heat collecting operation with a COP of 23.2 on a sunny day and 7.4 on a cloudy day, the COP of heat dissipation operation at night was 4.5; 3) the stable and efficient long-term operation can be expected by the daily cycle operation method combining a ground heat exchanger and a sky heat source heat pump; 4) the floor heating heat pump achieved a stable operation with a COP of 11.5 based on a 1 month experiment in Chiba, Japan; 5) a water source heat pump for hot water supply was developed. It is necessary to adjust the operation method and equipment since the performance was lower than expected; 6) based on the results of long-term operation and representative day in Chiba, Japan, the system realized a heating operation with COP of 8.4 and a cooling operation with COP of 5.3.
In recent years, Multi-split packaged air-conditioning systems have recently become commonplace in office buildings in Japan, and in many cases one space is served by several indoor air-conditioning units. The advantage of a multi-split packaged air-conditioning system is that each indoor unit can be operated and controlled individually, with users being able to change the temperature settings of the indoor units as desired. However, this can cause air-conditioning control problems such as a deterioration in mutual interference between adjacent indoor units. In particular, when each air-conditioned zone has a different internal load and set temperature, the sensor temperatures are influenced by disturbances, the indoor units are driven harder than they need be, energy consumption increases, and indoor air quality worsens.
In this study, we carried out CFD analyses incorporating MIMO MPC that controls each zone while considering the thermal environment between adjacent zones in an office space in which the set temperature differs between zones. Furthermore, we showed the effectiveness of this method by comparing it with SISO MPC.
Based on the results, the following was found out.
1. When comparing the outlet air temperatures of the respective cases, the fluctuation range of the outlet air temperatures of the periWS and inW02 zones where the set temperature is 26°C is large in CASE 1 but small in CASE 2.
2. The averaged room air temperature in the zone where the set temperature was 27 °C showed almost the same behavior in both control methods, but comparing the behavior of the occupancy-area sensor temperature at each point, the temperature fluctuation range in SISO MPC was large but that in MIMO MPC was small. The reason is presumed to be that the fluctuation of the room temperature was suppressed in MIMO MPC in accordance with the difference in the behavior of the outlet air temperature of the adjacent zone.
3. From the distribution of temperature and flow velocity vectors, it was confirmed that not only the sensor temperature but also the entire work space was controlled to the set temperature in each zone.
Thermo-Active Building System (TABS) is air conditioning system which utilizes the building frame as thermal storage part and radiation surface, and has been introduced in Japan in recent years. TABS offers higher energy efficiency, a more comfortable environment for workers and has advantages such as peak shift, reduction of heat source capacity and cost reduction by using large thermal mass. Also, control performance is important to create a comfortable thermal environment because the thermal response of the ceiling surface temperature is slow due to the large thermal mass.
Therefore, research and development of new control methods is progressing. In particular, Model Predictive Control (MPC), that determines the current value of the optimal manipulated variable pattern while predicting the behavior of a future controlled variable, is attracting attention.
In this study, we proposed MPC as optimal control method for an air conditioning system with large thermal mass. Moreover, we showed the effectiveness of this method by comparing conventional control method using coupled analysis of CFD analysis integrating general-purpose control simulator.
The following results were obtained:
1. MPC had optimized the manipulated variable (water flow rate) to satisfy the constraint conditions while taking into account the future controlled variable, internal load and set point. Therefore, the control error of ceiling temperature from set point in the case of MPC was smaller than ON/OFF control.
2. MPC has the effect of reducing about 12% of the energy consumption required for cooling and transport power of piping water.
3. It was confirmed that not only the sensor location but also the working space satisfied the comfortable range at 1.1m above the floor.
District energy system is facing on the risk of climate change. IPCC alarmed that the mean temperature would be rise by up to 4 °C by the end of the 21st century if there is no effort to reduce greenhouse gas emission in the fourth report. Japanese government has published weather prediction data called “Database for Policy Decision-Making for Future Climate Change” (hereafter d4PDF) to be utilized for study regarding to global warming.
This study aims to predict the effect of CGS (cogeneration system) and thermal storage after a mean temperature increase of 4°C (hereafter 4°C-Rise) with d4PDF and ENEPRO21, focused on the DHC system of Minatomirai 21 Area (hereafter MM21). In order to carry out this, this study utilized the data of the predicted heating and cooling demand of MM21 Area from the previous study: “Analysis of Influence of Climate Change on Demand and System of Heating and Cooling Predicted by d4PDF”. And the three scenarios were set up which were the Basic System Cases, the Thermal Storage Cases, and the CGS Cases.
As a result of simulation of the Basic System Cases, this study predicts what the amounts of annual primary energy consumption and CO2 emission will rise up 103.5%～103.8% and 103.7%～104.0% after 4°C-Rise. COP will increase from 0.98 to 1.01. The make-up water, the cooling water flow rate of cooling tower, and the waste heat will go up to 129.9%～132.0%, 162.3%～164.6%, and 163.5%～164.1% respectively. In average temperature, the effect of the thermal storage is that the amount of annual primary energy consumption and CO2 emission decreases by 0.6% and COP increases by 0.01. The amount of make-up water, cooling water flow rate of cooling tower, and the waste heat decrease by 6.0％, 6.2%, and 7.0% respectively. In the temperature after 4°C-Rise, the primary energy will go down 0.8～1.2% and COP will go up 0.01～0.02. The amount of make-up water, cooling water flow rate of cooling tower, and waste heat will be reduced by 5.7％～7.5%, 5.3%～7.6%, and 6.2%～8.2%. In conclusion, the effect of thermal storage in the temperature after 4°C-Rise is greater than in average temperature. As an effect of CGS, the primary energy saving rates in the temperature of average year and the temperature after 4°C-Rise are 33.48% and 32.38%, based on theoretical electro-thermal ratio. Compared with the results of ENEPRO21 simulation, in the average temperature, CGS reduces the primary energy consumption by 20.4%. And COP rise by 0.24. The amount of CO2 emission decreases by 22.3%. However, the amounts of make-up water waste heat increase by 16.4% and by 47.1%. In the temperature after 4°C-Rise, the effect of CGS is that the primary energy consumption will go down 20.8%. And COP will go up by 0.24. CO2 emission will decrease by 22.7%. The amount of make-up water will grow by 8.4%. The amount of waste heat will increase by 31.8%. To sum up, the effects of CGS in the temperature of average year and the temperature after 4°C-Rise are predicted to be on a similar level.