AREN 4110/5110 BUILDING ENERGY SYSTEMS ENGINEERING Spring 2024 Project Information PROJECT 2: INDUSTRIALIZED CONSTRUCTION You have been hired as the principal design engineer by a startup company attempting to develop volumetric mod- ules for industrialized construction serving the multifamily housing market. The company develops and delivers from its new factory, a former train depot, volumetric modules 20 m long, 5 m wide, and 3 m tall, with two 9 m long rooms on each side, separated by a 2 m hallway. Two modules are each aligned along the long axis to form two one-bedroom apartments with 90 m² (2x5mx9m) floor area, one on each side of the hallway, as shown in Figure 1 below. Module A will include the kitchen and liv- ing area, with an entry door from the hallway and a small balcony accessed by a sliding glass patio door. Module B will include the bedroom, bathroom, laundry, and all mechanical equipment. The bedroom will have a large window on the exterior wall. Within each apartment, Module A and Module B are connected by one or more doorways. 2.00m 20.00m Module A Module B 11 Figure 1: Two volumetric modules create two apartments separated by hallway, with forty apartments in the building The multifamily building will have four floors with ten modules per floor, creating ten one-bedroom apartments per floor, for a total of 40 apartments in the new building. The four residential floors will sit on top of a common base- ment. Module B is to be equipped with two energy pods, one for each apartment. The energy pod integrates and delivers all building services, i.e., heating, cooling, dehumidification, ventilation, and domestic hot water. The energy pods are designed to support an all-electric building in which water-to-air heat pumps deliver either heating or cooling and are connected to a common water loop that runs throughout the building. Heat pump hot water heaters draw their source of heat from the same building loop to deliver domestic hot water to a 200 L hot water storage tank that serves showers, fixtures, and appliances. Tenants are expected to have their own laundry facilities, i.e., washer and dryer. The dryer is to be a heat pump dryer, also connected to the building loop, that does not require any provision for exhaust. Each apartment thus features three heat pumps: one for heating and cooling, one for domestic hot water, and one for the dryer. The energy pods provide mechanical ventilation with energy recovery using a crossflow air-to-air heat exchanger delivering ventilation air according to ASHRAE Standard 62.2-2022. The energy pods are also a central hub for fire protection and domestic plumbing, including all domestic cold and hot water, waste, and vent piping. While you will not be evaluating any fire protection or domestic plumbing designs for this project, it would be logical to con- sider locating the energy pods adjacent to kitchen, bath, and laundry facilities. Page 1 of 4 April 2, 2024 AREN 4110/5110 BUILDING ENERGY SYSTEMS ENGINEERING Spring 2024 Figure 2 shows a schematic diagram of a water loop heat pump system in a commercial building, with multiple wa- ter source heat pumps connected to the common building water loop. It is common to have the building loop con- nected to a boiler and cooling tower as a common heat source and sink, respectively. Cooling Tower Boiler -Pumps Horizontal WLHP (typical) Supply Piping Return Piping Figure 2: Water loop heat pump system schematic for conventional boiler and cooling tower configuration In our case, our building uses a ground loop as the heat source and heat sink. The building has its own ground source heat exchanger (GSHE) with bore holes extending 100 m into the ground, connected to the water loop in the building via a plate frame heat exchanger. The GSHE was previously constructed during site preparation. The water coming from the GSHE is delivered to the plate frame heat exchanger, located in a mechanical space in the basement, with a constant temperature of 10°C. The ground loop has a variable speed pump assembly that maintains a temperature difference of 5°C for the ground water, i.e., when the building's water loop is rejecting heat to the ground in the summer, the water returned to the ground is at a temperature of 15°C, while during the winter, when heat needs to be added to the water loop, the water returned to the ground is at a temperature of 5°C. The choice for ground coupled heat pumps is motivated by the elimination of electric backup heat that would otherwise be neces- sary for airsource heat pumps in cold climates such as Madison, WI. This electric backup heat would require signifi- cant electrical distribution systems upgrades that the electric utility desperately wants to avoid, given all the other new electric loads expected to burden the grid such as electric vehicles. Design Assignment April 2, 2024 Page 2 of 4 AREN 4110/5110 BUILDING ENERGY SYSTEMS ENGINEERING Spring 2024 • • Modular apartment design O You are expected to develop a floorplan for the one-bedroom apartments including one bedroom, one bathroom, living room, kitchen, laundry area, and storage. Figure 1 shows the basic shape of volumetric modules and the apartments. While the figure shows loca- tions for doors and wall openings, you are welcome to design the apartments as you choose within the specified volumes of the modules and apartments. ○ The two energy pods, described in more detail below, should be placed in Module B. Building assumptions O O O O O Project location: Washington DC Building orientation: Long axis is east to west, windows face north and south Building envelope: Opaque construction: ASHRAE Wall 5 (see Appendix C for properties), with the exception that the insulation is 15 cm thick and has an R-value of 3.4 m²°C/W. Windows and patio door: Low-emissivity double-pane with U = 1.5 W/m²°C and SC = 0.42 Occupancy: Assume continuous occupancy of two persons per one-bedroom apartment. Internal gains: Assume design lighting levels of 4 W/m² and miscellaneous equipment of 6 W/m² of floor area. Assume equipment operates continuously and lighting operates only between the hours of 06:00-08:00 in the morning and 19:00-23:00 in the evening for a total of six hours per day. While the ground floor and top floor will have somewhat different heating and cooling loads, you will model level 2 as the typical floor and assume each floor has identical loads. Building energy systems ○ ○ о A dedicated ground loop exchanges heat with the building loop through a plate frame heat exchanger (PFHX). Assumptions for PFHX: • water supply to building = 10 °C water returned to ground in heating = 5 °C water returned to ground in cooling = 15 °C A building water loop runs through the building and is connected to heat pumps in each residential unit. These heat pumps, including those for space conditioning, water heating, and clothes drying, add heat to or draw heat from the building water loop. All mechanical equipment in each residential unit should be placed in a single integrated energy pod (ePod) within the unit. The pods on each floor are expected to be aligned ver- tically, with all plumbing and HVAC piping connecting in the basement below. While the ePods will be in Module B, it is expected that there will be a single vertical chase for the pair of apartments shown in Figure 1, aligned with one of the two ePods. That is, there should be a total of five vertical chases for the four-story, forty apartment building. ○ Your main task for this project is to design the modular ePods that are repeated through- out the building. ○ Space conditioning system о Each apartment has a single water-to-air heat pump to meet both heating and cooling needs. Ventilation system Each apartment will have its own ventilation and exhaust, with dedicated outdoor grilles on the apartment façade. April 2, 2024 Page 3 of 4 AREN 4110/5110 BUILDING ENERGY SYSTEMS ENGINEERING о Exhaust ■ Spring 2024 Ventilation air will be conditioned by an energy recovery ventilator (ERV) using bathroom exhaust air. The exhaust from the toilet will precondition the incoming ventilation air through the ERV. The exhaust is continuous at the required ventilation flow rate. The water heating system comprises a 200 L water storage tank and a dedicated water-to- water heat pump. ○ The clothes dryer is a heat pump dryer that does not require any exhaust. Workflow: о Ο ○ O O O O о о Space design for each of the two standard apartments (north-facing and south-facing). Each apartment has a single bedroom and will be occupied by two people. The layout should include a central ePod for all mechanical and plumbing equipment. Consider the adjacency of the kitchen, bathroom, and laundry as well as HVAC air distribution. Ventilation calculation using ASHRAE 62.2-2022 (Available as read-only document at https://ashrae.iwrapper.com/ASHRAE_PREVIEW ONLY STAND- ARDS/STD_62.2_2022). Refer to Section 4.1.1 and Equation 4-1b. Load calculations using thermal network methodology of the starter file located in the Canvas P2 folder. ePod design to accommodate all required equipment, to horizontally connect to the out- doors for ventilation and exhaust. The ePod should connect the occupant needs to the equipment in the pod. There should be horizontal connectivity between the two apart- ments sharing the modules to allow a shared mechanical shaft. The mechanical shaft will provide vertical connectivity to adjacent volumetric modules above or below. Select a water-to-air heat pump for each apartment based on load calculations. Select a water-to-water heat pump for each apartment water heater. Select a heat pump clothes dryer for each apartment. Layout all ductwork for a) ventilation and b) bathroom exhaust systems. No pressure drop calculations are required. Layout the piping in each volumetric module to connect the three heat pumps to the building water loop. Layout the piping for the building water loop that connect all the apartments and pods in the building. You do not need to perform sizing or pressure loss. Submittals: • ○ 00 ○ Ο 0 0 0 A single PDF file Clear identification of project group, group members, and location of design. Executive summary Description of the architectural and ePod designs of the apartments and modules, includ- ing design rationale. Isometric drawings of the ePods, including equipment locations, to effectively communi- cate your design to the startup company leadership. One-line diagrams of piping and ducting systems within the modules and of the building water loop connecting the modules. Summary of calculations and selections with appropriate tables of results. Appendix: Representative EES load calculation code for one zone, including formatted equations. 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