SEARCH · Engineering Papers

Results for “THERMOSTATS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31

All sources NASA NTRS DOE OSTI

DOE OSTI2014

Technology Solutions Case Study: Boiler Control Replacement for Hydronically Heated Multifamily Buildings, Cambridge, Massachusetts

The ARIES Collaborative, a U.S. Department of Energy Building America research team, partnered with NeighborWorks America affiliate Homeowners' Rehab Inc. (HRI) of Cambridge, Massachusetts, to study improvements to the central hydronic heating system in one of the nonprofit's housing developments. The heating controls in the three-building, 42-unit Columbia Cambridge Alliance for Spanish Tenants housing development were upgraded. Fuel use in the development was excessive compared to similar properties. A poorly insulated thermal envelope contributed to high energy bills, but adding wall insulation was not cost-effective or practical. The more cost-effective option was improving heating system efficiency, which faced several obstacles, including inflexible boiler controls and failed thermostatic radiator valves. Boiler controls were replaced with systems that offer temperature setbacks and one that controls heat based on apartment temperature in addition to outdoor temperature. Utility bill analysis shows that post-retrofit weather-normalized heating energy use was reduced by 10%-31% (average of 19%). Indoor temperature cutoff reduced boiler runtime (and therefore heating fuel consumption) by 28% in the one building in which it was implemented. Nearly all savings were obtained during night which had a lower indoor temperature cut off (68°F) than day (73° F). This implies that the outdoor reset curve was appropriately adjusted for this building for daytime operation. Nighttime setback of heating system supply water temperature had no discernable impact on boiler runtime or gas bills.

ARIES↗

DOE OSTI2015

Building America Case Study: Field Performance of Inverter-Driven Heat Pumps in Cold Climates - Connecticut, Massachusetts, and Vermont

New inverter-driven ASHPs are gaining ground in colder climates. These systems operate at sub-zero temperatures without the use of electric resistance backup. There are still uncertainties, however, about cold-climate capacity and efficiency in cold weather and questions such as measuring: power consumption, supply, return, and outdoor air temperatures, and air flow through the indoor fan coil. CARB observed a wide range of operating efficiencies and outputs from site to site. Maximum capacities were found to be generally in line with manufacturer's claims as outdoor temperatures fell to -10 degrees F. The reasons for the wide range in heating performance likely include: low indoor air flow rates, poor placement of outdoor units, relatively high return air temperatures, thermostat set back, integration with existing heating systems, and occupants limiting indoor fan speed. Even with lower efficiencies than published in other studies, most of the heat pumps here still provide heat at lower cost than oil, propane, or certainly electric resistance systems.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2015

Development of Personalized Radiant Cooling System for an Office Room

The building industry nowadays is facing two major challenges increased concern for energy reduction and growing need for thermal comfort. These challenges have led many researchers to develop Radiant Cooling Systems that show a large potential for energy savings. This study aims to develop a personalized cooling system using the principle of radiant cooling integrated with conventional all-air system to achieve better thermal environment at the workspace. Personalized conditioning aims to create a microclimatic zone around a single workspace. In this way, the energy is deployed only where it is actually needed, and the individual s needs for thermal comfort are fulfilled. To study the effect of air temperature along with air temperature distribution for workspace, air temperature near the vicinity of the occupant has been obtained as a result of Computational Fluid Dynamics (CFD) simulation using FLUENT. The analysis showed that personalized radiant system improves thermal environment near the workspace and allows all-air systems to work at higher thermostat temperature without compromising the thermal comfort, which in turn reduces its energy consumption.

CFD↗

DOE OSTI2016

Building America Case Study: Supplemental Ductless Mini-Split Heat Pump in the Hot-Humid Climate, Brevard and Volusia Counties, Florida

"The BAPIRC team and Florida Power and Light (FPL) electric utility pursued a pilot phased energy-efficiency retrofit program in Florida by creating detailed data on the energy and economic performance of two levels of retrofit - simple and deep. For this Phased Deep Retrofit (PDR) project, a total of 56 homes spread across the utility partner's territory in east central Florida, southeast Florida, and southwest Florida were instrumented between August 2012 and January 2013, and received simple pass-through retrofit measures during the period of March 2013 - June 2013. Ten of these homes received a deeper package of retrofits during August 2013 - December 2013. A full account of Phase I of this project, including detailed home details and characterization, is found in Parker et al, 2015 (currently in draft). Phase II of this project, which is the focus of this report, applied the following additional retrofit measures to select homes that received a shallow retrofit in Phase I: supplemental mini-split heat pump (MSHP) (6 homes), ducted and space coupled heat pump water heater (8 homes), exterior insulation finish system (EIFS) (1 homes), window retrofit (3 homes), smart thermostat (21 homes: 19 NESTs; 2 Lyrics), heat pump clothes dryer (8 homes), and variable speed pool pump (5 homes).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2017

Preventing conflicts among bid curves used with transactive controllers in a market-based resource allocation system

Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. One of the disclosed embodiments is a method for operating a transactive thermostatic controller configured to submit bids to a market-based resource allocation system. According to the exemplary method, a first bid curve is determined, the first bid curve indicating a first set of bid prices for corresponding temperatures and being associated with a cooling mode of operation for a heating and cooling system. A second bid curve is also determined, the second bid curve indicating a second set of bid prices for corresponding temperatures and being associated with a heating mode of operation for a heating and cooling system. In this embodiment, the first bid curve, the second bid curve, or both the first bid curve and the second bid curve are modified to prevent overlap of any portion of the first bid curve and the second bid curve.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2017

Building America Case Study: Impact of Improved Duct Insulation on Fixed-Capacity (SEER 13) and Variable-Capacity (SEER 22) Heat Pumps, Cocoa, Florida

A new generation of central, ducted variable-capacity heat pump systems has come on the market, promising very high cooling and heating efficiency. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they vary their cooling and heating output over a wide range (approximately 40 to 118% of nominal full capacity); thus, staying 'on' for 60% to 100% more hours per day compared to fixed-capacity systems. Current Phase 4 experiments in an instrumented lab home with simulated occupancy evaluate the impact of duct R-value enhancement on the overall operating efficiency of the variable-capacity system compared to the fixed-capacity system.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2017

Building America Case Study: Residential Mechanical Precooling, Roseville, California

Precooling is an operational strategy with potentially no up-front cost that cools occupied spaces earlier in the day to minimize or avoid afternoon air conditioner operation. In its simplest form, precooling can be implemented by scheduling air conditioner operation to reduce thermostat setpoints between 2 degrees and 6 degrees F below typical comfort settings in advance of the on-peak time period.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2017

Building America Case Study: Impact of Improved Duct Insulation on Fixed-Capacity (SEER 13) and Variable-Capacity (SEER 22) Heat Pumps, Cocoa, Florida

BA-PIRC↗

DOE OSTI2017

Building America Case Study: Residential Mechanical Precooling, Roseville, California

ARBI↗

DOE OSTI2018

Laboratory Resources and Techniques to Evaluate Smart Home Technology: Preprint

Smart home technologies promise to make residential buildings more comfortable, less costly to operate, more energy efficient, and more integrated with the grid, but these systems are difficult to evaluate in traditional laboratory spaces. To aid in the development and evaluation of new home energy management systems (HEMS), NREL built the Systems Performance Laboratory (SPL) within the Energy Systems Integration Facility. SPL has electrical infrastructure for three residential buildings, complete with smart meters, breaker panels and a full complement of major and minor appliances in each 'home.' Cord and plug power connections mean that appliances can easily be swapped for different models. Distributed energy resources (DER), such as residential photovoltaic (PV) inverters and home batteries, are also available for integration. Sensors monitor the power consumption of all loads and controllers can simulate occupancy to drive the appliances in realistic ways. A novel hardware-in-the-loop application was developed to ensure air conditioner cycling by combining a building simulation with a physical air conditioner and a thermostat, which allows us to simulate performance in any climate with any building construction. Another application of the hardware-in-the-loop technique uses a grid simulation to model the grid impact for different control strategies related to smart home technologies. This laboratory is a powerful, flexible tool that can be employed to evaluate the effect that home energy management and other smart home technologies will have at the appliance, whole-home, and distribution feeder levels - all of which are important perspectives for different stakeholders.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2014

Fast DR: Controlling Small Loads over the Internet

Current state-of-the-art demand response systems are expensive due to extreme reliability constraints in telemetry, control, and metering. The typical cost of enabling a site for regulation services is between $50k and $80k. These costs are orders of magnitude too high for small loads to participate in high-value grid services. Traditional demand response (DR) schedules events in advance and provides basic on/off control. We developed fast DR measurement and communication technologies, which are scalable cost-effective demand response systems with sufficient reliability for real-time control and monitoring of loads over the internet, and we demonstrated an example system for under $100. We installed FastDR systems for lighting, motor, and thermostat control along with power metering at a total of 10 sites, including 6 commercial buildings and 4 residential buildings. This demonstration addressed the following important methodological questions: 1) Can we reliably control loads simultaneously and with low latency across multiple sites within a specified response time; 2) How reliable is using the internet or 4G cellular network as the mode of control and metering; and 3) Can existing Smart Meters provide data for real-time telemetry services. Testing shows fast DR is capable of control to response in 4 seconds and loads complete transition in seconds to less than one minute depending on load type. We demonstrated 4s regulation services and synchronized load control, and we successfully met specifications for ancillary services across the US. Telemetry via the 4G cellular network demonstrated 94.5% success rate, and residential Internet demonstrated a 98% success rate.

Kiliccote, Sila↗

DOE OSTI2018

Characterizing Electric Grid System Benefits of MPC-Based Residential Load Shaping: Preprint

Routinely encouraging and discouraging residential electric load throughout the day will be increasingly critical in efficiently managing the smart grid to reliably deliver clean, low-cost electricity. Yet, manipulating the duty cycles of thermostatically controlled loads such as heating, air conditioning, and hot water heaters can have the effect of destabilizing or stabilizing the grid. This work explores the potential for price-responsive control of residential air conditioning to shape electric demand at the distribution feeder level to minimize electricity production costs. Physical models of the interplay between building thermal and electric loads are used to Simulate time-series temperature and load behavior. Instantaneous load-adding and load-shedding opportunities are quantified in more than 100,000 individual homes on 204 distribution feeders with results presented for 35 cities across the United States. In the context of distributed model predictive control, simulation of feeder-level response to a residential day-ahead 5-minute pricing vector to 2,146 homes highlights an aggregate impact of flexible loads.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2018

Leveraging Zone Air Temperature Data to Improve Physics-Based Energy Simulation of Existing Buildings

The paper introduces a hybrid modelling approach that enhances the accuracy and usability of physics-based energy simulation for existing buildings. The approach leverages measured zone air temperature data streams -- increasingly available from smart thermostats -- to derive difficult-to-obtain input parameters for internal thermal mass and infiltration airflow rates. It does so using a reformulated inverse heat balance algorithm. We implemented the inverse algorithms in EnergyPlus and used LBNL's Facility for Low Energy eXperiments (FLEXLAB) for demonstration and validation

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2018

Bidirectional shape memory device

A resistively heated shape memory polymer device is operated using resistive heating to heat the shape memory polymer device. The resistively heated shape memory polymer device is made by providing a wire that includes a resistive medium. The wire is coated with a first shape memory polymer. The wire is exposed and electrical leads are attached to the wire. In one embodiment the shape memory polymer device is in the form of a clot destruction device. In another embodiment the shape memory polymer device is in the form of a microvalve. In another embodiment the shape memory polymer device is in the form of a micropump. In yet another embodiment the shape memory polymer device is in the form of a thermostat or relay switch.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Behind-the-meter Transctive Control Approach for Home Energy Management System

Energy efficiency serves as an essential part of demand-side solutions to address the challenges of energy security and carbon emission, and ensure a reliable, affordable and sustainable energy system. In this paper, a behind-the-meter transactive market is proposed for the home energy management system to achieve energy reduction by coordinating home appliances through market bidding and clearing. The proposed approach can achieve the optimal coordination by taking into account the home owner's preferences of energy reduction over different appliances. Thermostatically controlled loads (TCLs) including air conditioner and water heater are considered as the example to illustrate the controller design. The proposed controllers for TCLs can translate the trade-off between energy saving and temperature discomfort into the bidding information. The simulation results demonstrate the effectiveness of the proposed behind-the-meter transactive design for energy efficiency.

Lian, Jianming↗

DOE OSTI2018

Bidirectional shape memory device

Marion, III, John E.↗

DOE OSTI2018

Completing the Connected Home with Smart Window Shades

Heat transfer through windows accounts for a significant percentage of a building’s energy use and adds substantially to the peak cooling load of a home. Window attachment manufacturers currently offer motorized shading devices for certain product lines, but this automation is typically marketed as a convenience and security feature for the homeowner and often does not include energy optimized control algorithms or dynamic and responsive features. This paper describes the experimental results of testing the energy performance of high-efficiency, dynamically operated, cellular shades in Pacific Northwest National Laboratory’s (PNNL) Lab Homes. The results of both heating and cooling season experiments will be presented, where testing is designed to assess the whole home energy savings resulting from both the thermal insulating properties as well as the automated and dynamic control strategies of shading devices. Control schemes tested include common “connected home” strategies where controls are integrated and coordinated between the window shading device, building thermostats, and external sensors. The presentation will also include results from testing designed to examine the benefits (in terms of comfort, energy savings, and responsiveness) of coordinating the operation of cellular shades with HVAC as a demand-response measure. These experiments demonstrate that highly insulating, dynamic window coverings that are reliably controlled can dramatically reduce the heating and cooling energy associated with windows and should be considered an important component of any “smart” home design.

energy savings, cellular shades, honeycomb shades,↗

DOE OSTI2020

Method and device for controlling heat pump

A method for controlling a heat pump is provided. A working mode of the heat pump is determined. Based on a determination that the working mode of the heat pump is a heating mode, an ambient temperature of the heat pump is determined. Based on a determination that the ambient temperature of the heat pump is higher than a first predetermined temperature, a first compressor of the heat pump is operated. Based on a determination that the ambient temperature of the heat pump is lower than the first predetermined temperature, both the first compressor and a second compressor of the heat pump are enabled to operate, in response to a two-stage thermostat. The first compressor and the second compressor are coupled in parallel. The method allows the heat pump to be suitable for a cold climate.

42 ENGINEERING↗